Search

In this work, we demonstrate the use of a machine learning (ML)-based statistical approach to model and analyze the impact of the fabrication processes on the threshold voltage in recessed gate AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors. First, we employ a ML-based Tikhonov regularization approach using the input of 19 different processing splits to generate a multivariable analytical equation that considers four critical processing parameters, such as the remaining AlGaN depth, ex-situ wet clean, in-situ plasma, and gate dielectric. Furthermore, the artificial neural network-based approach, which cannot be used to further analyze the impact of the process, is implemented for the comparison. Second, the results from this analytical equation show a nice agreement with the measured threshold voltage, indicating a successful correlation between the processing parameters and the threshold voltage. Finally, the impact of each process on the threshold voltage can be analyzed through the coefficient value related to each process, which can be a useful guidance for the device optimization toward the targeted performance. [ABSTRACT FROM AUTHOR]

III-V heterostructure based high electron mobility transistors (HEMTs) offer superior performance as compared to CMOS silicon transistors owing to the high mobility in the 2D electron gas (2DEG) channel at the heterostructure interface. Gallium nitride (GaN) based HEMTs are also suitable for high power and high temperature applications. GaN has a rich offering of material properties spanning domains of non-linear optics, piezoelectric micro-electro-mechanical systems, and monolithic microwave integrated circuits. In this paper, we propose HEMT inspired III-V electro-optic modulator topologies and study the light interaction with 2DEG in such structures. We analyze the electroabsorption and electrorefraction on account of the 2DEG interaction with light and present a design framework to selectively leverage the desired mechanism of modulation. Our analysis suggests that modulation index of electrorefractive modulation in a HEMT-like structure is comparable to silicon photonic modulators. By leveraging the higher electron mobility in these material platforms, the device concepts proposed here could potentially be used to design electro-optic modulators with extremely high modulation rates. [ABSTRACT FROM AUTHOR]

In this paper, fully recessed-gate GaN MISFETs with two different gate dielectrics, i.e., plasma-enhanced atomic layer deposition (PEALD) SiN and ALD Al2O3 gate dielectric, are used to study the origin of positive bias temperature instability (PBTI). By employing a set of dedicated stress-recovery tests, we study PBTI during the stress and relaxation. Hence, a defect band model with different distributions of defect levels inside the gate dielectric is proposed, which can excellently reproduce the experimental data and provide insightful information about the origin of PBTI in GaN MISFETs. The results indicate that the serious PBTI in the device with PEALD SiN is mainly due to a wide distribution of defect levels ( \sigma \sim 0.67 eV), centered below the conduction band of GaN ( E_{C} -0.05 eV), and can be easily accessed by the channel carriers already at a low-gate voltage. On the other hand, ALD Al2O3 gate dielectric shows a narrower distribution of defects ( \sigma \sim 0.42$ eV), which are far from the conduction band of GaN ( E_{C} +1.15 eV). This observations explain the improved PBTI reliability observed in devices with ALD Al2O3. [ABSTRACT FROM AUTHOR]

We focus on slow de-trapping phenomena in AlGaN/GaN MIS-HEMTs with a bilayer dielectric ( in-situ Si 3 N 4 /Al 2 O 3 ) with two different thicknesses of in-situ Si 3 N 4 (10 nm and 5 nm). By using a “filling pulse” at a positive gate voltage, a trap with activation energy of 0.69–0.7 eV was identified to be responsible for the V TH shift. Based on literature, filling conditions, and the simulated band diagrams, this trap is most probably located at the interface between the dielectrics and AlGaN barrier. A physical model is proposed to explain the V TH shift due to the trapping/de-trapping phenomena based on the occupation dynamics of donor traps at the interface between the in-situ Si 3 N 4 /Al 2 O 3 and the AlGaN barrier. [ABSTRACT FROM AUTHOR]

The reliability of Au-free Ohmic contacts has been evaluated under a constant current stress (500 mA/mm) in a high temperature environment (150 °C, 175 °C, and 200 °C). Two Ohmic contact schemes with different Ti/Al thicknesses (5 nm/100 nm and 10 nm/100 nm) have been tested. The results showed that the degradation of the resistance ( R increase ) is accelerated at a higher temperature condition. Moreover, R increase has a square root dependence with the time. This indicates that a diffusion process could be responsible for the observed degradation. This has been confirmed by means of physical failure analyses (FIB/TEM) performed on a highly degraded device: an apparent roughness of the interface between TiN and the Ohmic metal layer was observed. On top of this, Nitrogen out-diffusion into the Ohmic metal was observed in the EDS/EELS analyses, suggesting that a material diffusion phenomenon might play a role. In addition, we observed that the devices with a lower initial contact resistance ( R c ) showed lower degradation with respect to devices with a larger initial R c . This suggests that obtaining lower R c is beneficial not only for the performance but also for the reliability. [ABSTRACT FROM AUTHOR]

In this paper, performances of a 4H-SiC UMOSFET with split gate and P+ shielding in different configurations are simulated and compared, with an emphasis on the switching characteristics and short circuit capability. A novel structure with the split gate in touch with the P+ shielding is proposed. The key design issues for 4H-SiC UMOSFETs are trench gate dielectric protection and reverse transfer capacitance Crss reduction. Based on simulation results, it is concluded that a UMOSFET with a gate structure combining split gate grounded to the trench bottom protection P+ shielding layer and a current spreading layer is achieved to yield the best compromise between conduction, switching, and short circuit performance. The split-gate design can effectively reduce Crss by shielding the coupling between the gate electrode and the drain region. The P+ shielding design not only protects the oxide at trench bottom corners but also minimizes the short channel effect due to drain-induced barrier lowing and the channel length modulation. Trade-off of the doping concentration of current spreading layer for UMOSFET is also discussed. A heavily doped current spreading layer may increase Crss and influence the switching time, even though RON,SP is reduced. [ABSTRACT FROM AUTHOR]

Insulin-like growth factors (Igf1 and Igf2) play a key role in growth and development of vertebrates. In mammals, the expression of IGF s is regulated by estradiol-17β (E 2) via estrogen receptors (ESRs). The expression of igf s can also be regulated by E 2 in fish, while comparative study of this is still lacking. The present study examined tissue distribution of igfs and hepatic expression of igf s and esr s during gonad development in Scatophagus argus by real-time PCR. Serum E 2 concentration was measured by enzyme-linked immunosorbent assay (ELISA). The hepatic expression of igf s and esr s at gonadal phase III, incubated with either E 2 (0.1, 1 or 10 μM) alone or in combination with estrogen receptor antagonists-fulvestrant, MPP or PHTPP, was measured. igf1 and igf2 expressed highest in liver of both sexes. Igf1 , esr1 and esr2b expressions and serum E 2 concentration increased, while igf2 and esr2a expressions decreased, during ovary development. Igf s and esr s expressions increased while serum E 2 concentration maintained low during testis development. In females, E 2 incubation enhanced the expressions of igf1 and esr1 but inhibited that of igf2 and esr2a. Both fulvestrant and MPP inhibited up-regulation effect of E 2 on igf1 and esr1. Fulvestrant enhanced down-regulation effect of E 2 on igf2 and esr2a , but MPP conversely. In males, E 2 incubation enhanced the expressions of igf s, esr1 and esr2a. Fulvestrant and MPP inhibited up-regulation effect of E 2 on igf s and esr1. PHTPP inhibited igf1 and esr2 expressions in both sexes. Our results indicated that the expression of igfs is regulated by E 2 via Esrs in S. argus. Unlabelled Image • igf1 and igf2 was found to be expressed highest in the liver of both sexes in S. argus. • There is a correlation between the expression of igf s, esr s and serum E 2 concentration in S. argus. • It was first found in fish that E 2 regulates the expression of igf s via Esrs. • E 2 regualates the expression of igf1 via both Esr1 and Esr2 in female and male S. argus. • E 2 regualates the expression of igf2 via Esr2a and Esr1 in female and male S. argus , respectively. [ABSTRACT FROM AUTHOR]

In this article, we demonstrate that a physics-based compact model can facilitate to analyze the reliability using an example of γ-ray induced instability in AlGaN/GaN HEMTs. First, the typical AlGaN/GaN HEMTs are subjected to the cumulative γ-ray irradiation, exhibiting the drain current (ID) increase. In order to further elucidation, the root cause, the compact model is implemented and calibrated with the pristine case. Then, ID – VG and ID – VD characteristics subjected to the γ-ray irradiation are fitted with the compact model. The extracted μ and Rc are consistent with the results obtained by the Hall measurement and circular transmission line measurement (C-TLM). By comparing the fitted curves with considering: 1) fitted μ (Rc is fixed as the pristine case) and 2) fitted Rc (μ is fixed as the pristine case), the shift of μ is identified as the root cause leading to the ID increase because of the better fitting results. Therefore, with the assistance of the physics-based compact model, the shift of the parameter can be further analyzed to understand the origin of the instability. [ABSTRACT FROM AUTHOR]

In this study, we comprehensively investigate the constant voltage stress (CVS) time-dependent breakdown and cycle-to-breakdown while considering metal-ferroelectric-metal (MFM) memory, which has distinct domain sizes induced by different doping species, i.e., Yttrium (Y) (Sample A) and Silicon (Si) (Sample B). Firstly, Y-doped and Si-doped HfO2 MFM devices exhibit domain sizes of 5.64 nm and 12.47 nm, respectively. Secondly, Si-doped HfO2 MFM devices (Sample B) have better CVS time-dependent breakdown and cycle-to-breakdown stability than Y-doped HfO2 MFM devices (Sample A). Therefore, a larger domain size showing higher extrapolated voltage under CVS time-dependent breakdown and cycle-to-breakdown evaluations was observed, indicating that the domain size crucially impacts the stability of MFM memory. [ABSTRACT FROM AUTHOR]

Gallium nitride high electron mobility transistors outperform Silicon devices due to their excellent physical properties. However, being an immature technology, it exhibits dynamic on-state resistance ($R_{\text{ds}, \text{on}}$). This causes increased conduction loss and leads to reduced operating efficiency. To evaluate the dynamic $R_{\text{ds}, \text{on}}$ of the device, a measurement circuit is required. In literature, a standardized double pulse test is widely used for the measurement of $R_{\text{ds}, \text{on}}$. However, due to the uncontrolled off-state time and inability to independently adjust, the test conditions result in restricted measurement. This article proposes a measurement circuit of the device in power electronics operations. The circuit uses an H-Bridge-derived topology with capacitive storage to enable forward and reverse conduction mode measurement of the device. In all the modes, the circuit allows measurement from the first switching cycle and independent control over the testing conditions by using a hysteresis current control. The proposed measurement circuit is validated using simulation and experimentation. Finally, analytical efficiency compared with the state-of-the-art measurement circuits is provided. [ABSTRACT FROM AUTHOR]

In this paper, we propose and demonstrate to use of a single reflector with 68 segments to project vehicle low beam and high beam with the use of a GaN-based mini-LED matrix, which is a 5 × 6 LED die array. The design of the reflector is based on light field technology in considering etendue from the light source across the segments. The group of the segments with smaller etendue from the LED dies in the bottom 2 rows are used to project low beams. When the other LED dies are turned on, the reflector will project light upward and form the high beam. The selection of the turn-on LED dies in the mini-LED matrix can adjust the width of the illumination pattern so that an adaptive low/high beam can be performed. Besides, to extend the functionality of the headlamp module, we propose to dispense IR phosphor on LED dies in the high-beam zone of the GaN-based mini-LED matrix. Thus the vehicle can emit IR high beam, which can be imaged through a camera and can be incorporated with machine vision for an autonomous vehicle without using a complicated adaptive headlight to avoid glare. The proposed multi-function in spatial and spectral domains will be helpful to various applications with use of a mini-LED matrix. [ABSTRACT FROM AUTHOR]

In this paper, we review and add additional data and understandings on our findings on the two most common failure modes of GaN-based HEMTs: 1) permanent gate leakage current increase and 2) output current drop. We suggested that they have different origins and one is not necessarily correlated to the other. Yet, they can both concur to the device degradation. First, we demonstrate that the phenomenon of gate leakage current increase has a voltage-accelerated degradation kinetic. Therefore, the identification of the critical voltage for leakage increase is meaningless. We demonstrate that the time-to-breakdown tBD data are Weibull distributed and we prove that they represent intrinsic failures. According to our data, this phenomenon is not related to the inverse piezoelectric effect. Finally, a new degradation model for the gate leakage current increase based on the percolation path theory is proposed. Second, we show that the permanent output current drop is a consequence of the relaxation of AlGaN layer. This occurs by means of formation of crystallographic defects as described by the inverse piezoelectric degradation model. Finally, we show an excellent stability of devices with reduced Al content in the AlGaN barrier, proving the crucial role of strain in the reliability of AlGaN/GaN HEMTs. [ABSTRACT FROM AUTHOR]

This work demonstrates a trench isolated lateral double-implanted MOSFET (LDMOS) on Si-face in 4H-silicon carbide (SiC). A device $\vphantom {_{\int _{}}}$ where ${L}_{\textit {ch}} = 0.8\,\,\mu \text{m}$ and ${L}_{d} = 12\,\,\mu \text{m}$ shows an ${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ of 22.9 $\text{m}\Omega $ cm2 at a ${V}_{\text {GS}}$ of 20 V and a breakdown voltage (BV) of 1100 V, corresponding to a high BV2/ ${R}_{ \mathrm{\scriptscriptstyle ON},\text {sp}}$ of 55.5 MW/cm2. Devices that have different ${L}_{\text {ch}}$ , ${L}_{\text {JFET}}$ , ${L}_{d}$ , and P-top dose values are measured in order to investigate the effects of geometry on the static performance. Operations at 150 °C are measured to evaluate the temperature performance. Gate charge waveforms are also measured in order to include the switching performance in the evaluation. The ${R}_{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{G}$ and ${R}_{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{\text {GD}}$ values are calculated as 17.7 and $9.0~\Omega $ nC, respectively, which are promising for power-integrated circuit applications. [ABSTRACT FROM AUTHOR]

Effects of oxidation and nitric oxide (NO) post-oxidation annealing (POA) processes on the gate oxide integrity on 4H-SiC are investigated. Interface state density, flatband voltage, electron tunneling barrier height, breakdown field, and time-dependent dielectric breakdown are extracted. With the same NO POA condition, more nitrogen atoms are incorporated into wet oxide than dry oxide. The interface state density can be passivated effectively. At the same time, the electron tunneling barrier height at the SiO 2 /SiC interface approaches the ideal barrier height while positive charges would be introduced in oxide. NO annealing does not affect the breakdown field significantly. Regarding the time-dependent dielectric breakdown (TDDB) reliability, with increasing NO annealing time, the 10-year-projected intrinsic breakdown field decreases. It is concluded that NO annealing is effective in reducing the density of interface traps and hole traps originated from carboxyl defects, but excessive amount of nitrogen will turn into hole traps and thus deteriorates TDDB performance. • With the same NO POA condition, more nitrogen atoms are incorporated into wet oxide than dry oxide. • With nitrogen incorporation, the interface state density can be passivated effectively. • Wet oxidation results in slightly higher breakdown field while NO POA slightly reduces the breakdown field • With increasing NO annealing time, the 10-year-projected intrinsic breakdown field decreases for both wet and dry oxidation samples. • Excessive amount of nitrogen will turn into hole traps and thus deteriorates TDDB reliability of gate oxide on 4H-SiC. [ABSTRACT FROM AUTHOR]

In this article, a physics-based analytical model which considers the channel charge (Qch) for enhancement-mode p-GaN power high-electron-mobility transistors (HEMTs) is developed. First, by considering the same dynamic channel charge (dQch) for the Schottky/p-GaN junction capacitance (Cj,Sch) and the p-i-n-junction capacitance (Cp-i-n), due to the p-GaN/AlGaN junction and two-dimensional electron gas (2DEG) charge, the analytical formula to calculate the voltage drop in the p-GaN layer (VpGaN) is presented. Second, by implementing the analytical formulae in the advanced SPICE model (ASM) GaN model, the proposed physics-based model reliably fits the measured C – V and I – D – V – G characteristics of the samples under different processing conditions. This provides significant insight regarding the Mg concentration, the voltage drop at the Schottky metal/p-GaN junction (Vj,Sch), and the voltage drop at the p-GaN/AlGaN junction (Vp-i-n). Finally, the I – D – V – G and I – D – V – D characteristics of enhancement-mode p-GaN power HEMTs are modeled, displaying good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

The aim of achieving E-mode operations has led to the proposal of novel hybrid ferroelectric charge trap gate stack schemes. These schemes involve utilizing a combination of the charge trapping layer (CTL) and the ferroelectric laminated layer to positively shift the threshold voltage to a normally-off margin after initializing the gate pulse, thus achieving the Enhancement-mode (E-mode) characteristic. This study focuses on the forward gate bias time-dependent dielectric breakdown (TDDB) gate reliability in the E-Mode GaN MIS-HEMTs using ferroelectric charge trap gate stack (FEG-HEMT) with and without recess and investigates the impact of temperature on TDDB. The gate voltages required for operation with a 1 % failure rate over a 10-year period are 12.95 V and 10.22 V at 25 °C and 150 °C for both samples, respectively. Also, the examination of the stability of the recessed process by calculating the activation energies (0.7 eV) of both samples are demonstrated. The article also investigates the relationship between long-term reliability and short-term initialization by examining the transition point of the time-dependent failure curve. • The aim of achieving E -mode operations has led to the proposal of novel hybrid ferroelectric charge trap gate stack schemes. • This study focuses on the forward gate bias time-dependent dielectric breakdown (TDDB) gate reliability in the E-Mode GaN MIS-HEMTs using ferroelectric charge trap gate stack (FEG-HEMT) • The gate voltages required for operation with a 1% failure rate over a 10-year period are 12.95V and 10.22V at 25°C and 150°C for both samples, respectively. • Also, the examination of the stability of the recessed process by calculating the activation energies (0.7eV) of both samples are demonstrated. [ABSTRACT FROM AUTHOR]

In this work, the time-dependent dielectric breakdown (TDDB) analysis is performed to understand the gate oxide reliability in SiC MOSFETs with two different structures, i.e., planar and trench gate structures. We have discovered different gate leakage current behaviors between the SiC MOSFETs with planar gate (Sample A) and trench gate (Sample B) during the forward gate bias stress. Notably, the slight increase of the gate current during the stress and the negative activation energy (E a = −0.07 eV) observed in Sample A suggest that the hole generation caused by the impact ionization can be occurred during the forward gate TDDB tests. Furthermore, the SiC MOSFETs with trench gate structure (Sample B) exhibit the operation voltage of 55.7 V (exponential law) and 57.3 V (power law) for the 0.001 % failure of 30 years under 175 °C, indicating that SiC trench gate MOSFETs with enough thick gate dielectric (87.1 nm (bottom) and 77.9 nm (sidewall)) can have the promising forward gate TDDB stability. • The time-dependent dielectric breakdown (TDDB) analysis is performed to understand the gate oxide reliability in SiC MOSFETs • Different gate leakage current behaviors between the SiC MOSFETs with planar gate and trench gate • The negative activation energy observed in SiC planar MOSFETs suggests that the hole generation caused by the impact ionization • SiC trench gate MOSFETs with enough thick gate dielectric can have the promising forward gate TDDB stability. [ABSTRACT FROM AUTHOR]

This article reports that the enhanced forward gate bias time-dependent dielectric breakdown (TDDB) reliability and interface quality are achieved in 5-nm ferroelectric Hf0.5Zr0.5O2 (HZO) technologies by using the NH3 plasma interfacial layer (IL) treatment and microwave annealing (MWA). An orthorhombic crystalline phase is observed in the annealed HZO film with NH3 plasma IL treatment and MWA, and NH3 plasma IL treatment can suppress Hf/Zr interdiffusion. Metal-oxide-semiconductor capacitors (MOSCAPs) subjected to NH3 plasma IL treatment and 2100-W MWA also have a higher extrapolated operating voltage for a ten-year lifetime at 0.01% failure and lower interface state density (Dit) compared to the devices subjected to only rapid thermal annealing (RTA) at 600 °C. Therefore, NH3 plasma treatment and MWA are effective for improving the TDDB reliability and interface quality of the ultrathin ferroelectric HZO. [ABSTRACT FROM AUTHOR]

Herein, the gamma‐ray irradiation effect on ferroelectric HfAlOx capacitors for biomedical and space applications is investigated. The experimental results focus on the observation of ferroelectric polarization characteristics in support of different defect mechanisms induced by annealing, endurance cycling, and gamma‐ray irradiation. It is found that the HfAlOx with low Al doping of 6.5% become more vulnerable to radiation exposure, but a remarkable improvement in 9%‐Al‐doped HfAlOx due to less oxygen vacancies is demonstrated. In addition, the results also confirm that the fatigue property of ferroelectric HfAlOx capacitor is determined by the electric‐stress‐induced defect during endurance cycling, not mainly contributed by irradiation damage, which shows the potential for memory applications in rigorous irradiation environment. [ABSTRACT FROM AUTHOR]

Abstract Phoenixin (Pnx), a recently discovered neuropeptide, has been implicated in reproduction. Pnx mainly exists in two active isoforms, phoenixin-14 (Pnx-14) and phoenixin-20 (Pnx-20). However, little is known about the functions of Pnx in teleosts. To determine the roles of Pnx in the regulation of reproduction in Scatophagus argus , the physiological characterization of the Pnx was analyzed. During ovary development, the expression of pnx in phase IV was higher than in phase II and III in the hypothalamus. In the pituitary, pnx expression was highest in phase IV, moderate in phase III, and lowest in phase II. When hypothalamus and pituitary fragments were cultured in vitro with Pnx-14 and Pnx-20 (10 nM and 100 nM) for 6 h, the expression of GnRHR (gonadotropin releasing hormone receptor), lh (luteinizing hormone) and fsh (follicular stimulating hormone) in the pituitary increased significantly, except GnRH (gonadotropin releasing hormone) in the hypothalamus. Similarly, the expression of GnRHR , lh and fsh in the pituitary increased significantly after injecting S. argus with Pnx-14 and Pnx-20 (10 ng/g and 100 ng/g body weight (bw)), except GnRHR and fsh treated with 10 ng/gbw Pnx-20 in the pituitary and GnRHs in the hypothalamus. These results indicate that Pnx may not only stimulate the reproduction of the S. argus through the hypothalamic-pituitary-gonadal (HPG) axis, but also directly through the pituitary. Highlights • The hypothalamic expression of pnx in phase IV was significantly higher than in phase II and III during ovarian development. • pnx expression was highest in phase IV, moderate in phase III, and lowest in phase II in the female pituitary. • In vitro and in vivo Pnx treatments increase the expression levels of GnRHR , lh and fsh in the pituitary. [ABSTRACT FROM AUTHOR]

Abstract Phoenixin (Pnx) is an endogenous peptide known to be involved in reproduction and food intake in rats, with two active isoforms, phoenixin-14 (Pnx-14) and phoenixin-20 (Pnx-20). However, little is known about the functions of Pnx in teleost. Here, pnx was cloned and was detected in all tissues of both male and female in spotted scat (Scatophagus argus), including growth axis, hypothalamus, pituitary, and liver. Real-time PCR analysis showed that pnx in the hypothalamus increased significantly after 2 d and 7 d fasting, while reduced significantly after re-feeding (P < 0.05). When pituitary and liver fragments were cultured in vitro with Pnx-14 and Pnx-20 (10 nM and 100 nM) for 6 h, the expression of ghrhr (growth hormone-releasing hormone receptor) and gh (growth hormone) in the pituitary, and ghr1 (growth hormone receptor 1) in the liver increased significantly, except ghr2 (growth hormone receptor 2) incubated with 10 nM and 100 nM Pnx-20 and ghr1 incubated with 10 nM Pnx-20. Similarly, the expression of ghrhr and gh in the pituitary, as well as ghr1 and ghr2 in the liver, increased significantly after injecting S. argus with Pnx-14 and Pnx-20 (10 ng/g and 100 ng/g body weight). These results indicate that Pnx is likely to be involved in the regulation of food intake, and also regulates the growth of S. argus by increasing ghrhr and gh expression in the pituitary, ghr1 and ghr2 in the liver, and ghr1 directly in the liver. [ABSTRACT FROM AUTHOR]

The Scatophagus argus is a cultured marine teleost fish in which females grow faster and larger than males, therefore cloning the master sex-determination (SD) gene will be helpful for its sex control in aquaculture. A well-conserved Dmrt1 (doublesex- and mab-3-related transcription factor-1) gene, encoding zinc finger-like DNA binding motif (DM-domain) plays a critical role in sex determination and differentiation in vertebrates. Here, two pairs of sex-specific primers, Dmrt3-Marker-F/R and Dmrt1-Marker-F/R were developed from Dmrt3 and Dmrt1 transcripts in S. argus respectively. The single-nucleotide polymorphisms (SNP) at position −151 and 166 bp on the DNA amplified by Dmrt3-Marker-F/R are all homozygous CC GG genotype in females and heterozygous CG GA genotype in the males. The Dmrt1-Marker-F/R could only amplify a 3.2 kb fragment in males . Both Markers were confirmed in 246 adult S. argus (113 males and 133 females) from five populations in China. These results indicate that the sexes of S. argus are controlled by sex chromosomes (XX females, XY males). The nucleotide at position 166 bp of the DNA amplified by Dmrt3-Marker-F/R is found to be a donor splice site mutation (c.400 + 1G > A) in Dmrt3 which generates a truncated isoform. The truncated Dmrt3 is linked to male sex and thereafter named as Dmrt3△-Y, and its allele is the normal Dmrt3 on the X chromosome. The DNA amplified by Dmrt1-Marker-F/R is a fragment between exon 2 and exon 3 of a normal Dmrt1 implying that Dmrt1 is male-specific and located on the Y chromosome. A truncated Dmrt1 ( Dmrt1b ) was found to exist in both males and females. The Dmrt1b is with high similarity with Dmrt1 indicating Dmrt1b is the allele of Dmrt1 located on the X chromosome. RT-PCR revealed that Dmrt1 is highly expressed in the testes, while it is not expressed in the ovaries. Dmrt3△-Y is only expressed weakly in some of the testes, while it is not expressed in the ovaries. The testicular specifically expressed Dmrt1 is the candidate SD gene on the Y chromosome in S. argus . [ABSTRACT FROM AUTHOR]

Spexin (Spx), a novel neuropeptide, composed of 14 amino acid residues, is evolutionally conserved from fish to mammals. It has been suggested that Spx has pleiotropic functions in mammals. However, reports about Spx are very limited. To clarify the roles of Spx in the regulation of reproduction and food-intake in the spotted scat, the spx ( ssspx ) gene was cloned and analyzed. Analysis of the tissue distribution by RT-PCR showed that ssspx expression was widespread. During ovary development, expression of ssspx was found to be highest in phase II, moderate in phase III, and at its lowest level in phase IV. Ssspx expression was significantly down-regulated in the hypothalamus after treatment with E 2 both in vitro and in vivo . A significant increase of ssspx was observed after 2 and 7 days of food deprivation. However, the ssspx transcript levels in the 7 day fasting group decreased significantly after refeeding 3 h after the scheduled feeding time. This suggests that ssSpx may be involved in the regulation of reproduction and food-intake in the spotted scat. [ABSTRACT FROM AUTHOR]

Thimet oligopeptidase (Top) is a thiol-sensitive metallopeptidase with increased concentrations in brain and reproductive tissues. Prolyl endopeptidase (Pep) is another endopeptidase with high enzymatic activity in the brain. The two neuropeptidases are involved in the degradation of gonadotropin-releasing hormone. To clarify their roles in reproductive regulation, the spotted scat top (sstop) and pep (sspep) genes were cloned and analyzed. Tissue distribution by RT-PCR showed that sstop and sspep were more highly expressed in reproduction-related tissues than in other tissues. The sstop and sspep mRNA was detected in female hypothalamuses at phase II (oocytes at the perinuclear stage), phase III (oocytes forming the vitelline vesicle) and phase IV (oocytes at lipidic and proteic vitellogenesis stages). Both sstop and sspep were highly expressed in phase III, moderately in phase IV, and the lowest in phase II. The sstop and sspep genes were down-regulated in hypothalamuses after treatment with estradiol both in vitro and in vivo. It is suggested that Sstop and Sspep play significant roles in the regulation of reproduction and these results suggested an ssTop- and ssPep-mediated positive feedback mechanism of ovarian function. [ABSTRACT FROM AUTHOR]

To our knowledge, this is the first study to investigate the high-frequency (100–300 kHz) switching stability of SiC power devices at a Vds of 800 V during hard switching (HSW) and zero voltage switching (ZVS) operations. In this study, we proposed a topology for evaluating the switching dependencies (i.e., temperature, frequency, current, and duty cycle) in order to determine their flexibility in identifying circuit-level switching stability. We also evaluated the high-frequency switching stability of GaN power devices for comparison purposes. Overall, the results indicated that compared with GaN power devices, SiC power devices have higher dynamic drain-to-source on-resistance stability during ZVS and HSW high-frequency switching operations. • Investigate the high-frequency (100–300 kHz) switching stability of SiC power devices. • Propose a topology for evaluating the switching dependencies (i.e., temperature, frequency, current, and duty cycle). • Evaluate the high-frequency switching stability of GaN power devices for comparison purposes. • SiC power devices have higher dynamic drain-to-source on-resistance stability. [ABSTRACT FROM AUTHOR]

Estrogen receptors (Er) play a critical role in vitellogenesis. Three ers ( erα , erβ1 and erβ2 ) and vitellogenins (v tg-A , v tg-B and v tg-C ) subtypes were isolated in various fish species, while the contribution of each Er to the regulation of vtgs expression was not analyzed in detail. Here, erα , erβ1 and erβ2 were cloned and all were found to be expressed in female liver in Scatophagus argus . During proteic vitellogenesis stage, er α was simultaneously up-regulated, while er β 1 and er β 2 were not, with three vtgs in female liver. The effects of 17β-estradiol (E 2 ) alone or combined with Er antagonists on ers , vtgs mRNA expressions and Vtg protein content in incubated male liver were examined by real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. The expressions of erα , erβ1, vtgs mRNA and Vtg protein increased significantly after 24 h incubation with E 2 (0.1, 1 and 10 μM), while Er nonselective antagonist ICI 182 780 (0.01, 0.1 and 1 μM) significantly attenuated the up-regulation effects of E 2 on ers, vtgs mRNA and Vtg protein in a dose-dependent manner. Erα selective antagonist Methyl-piperidinopyrazole (MPP) (0.01, 0.1 and 1 μM) significantly attenuated the up-regulation effects of E 2 on erα , vtg-B , vtg-C mRNA and Vtg protein, while promoted the expression of erβ1 and vtg-A . Erβ selective antagonist Cyclofenil (0.01, 0.1 and 1 μM) attenuated the up-regulation effects of E 2 on erβ1 , erβ2 , vtg-A , vtg-C mRNA and Vtg protein while promoted the expression of erα and vtg-B . Our results suggest that the regulation of Ers on different vtgs was divergent in S. argus . [ABSTRACT FROM AUTHOR]

This paper investigates the robustness of normally-off High Electron Mobility Transistors (HEMTs) with p-GaN gate submitted to forward gate bias overstress. By means of combined DC and spectral analysis we demonstrate the following results: (i) the devices demonstrate a time-dependent failure mechanism; (ii) time to failure (TTF) can be described by a Weibull distribution with a shape factor higher than 1, suggesting a wear-out failure; (iii) the devices have an estimated 20-years lifetime for a gate voltage of 7.2 V; (iv) TTF is temperature-dependent, with an activation energy of 0.5 eV; (v) emission microscopy reveals the presence of hot spots, whose emission originates from yellow luminescence and/or hot electron radiation. [ABSTRACT FROM AUTHOR]

In this work, the relaxation analysis is performed to understand the V TH instability in FeFETs with two different dopants, i.e., Si and Gd. The FeFETs with different dopants show the different delay-after-write characteristics, i.e., Gd:HfO 2 FeFETs show a better delay-after-write stability compared to the case of Si:HfO 2 FeFETs. With the relaxation analysis, Si:HfO 2 FeFETs exhibit an obvious V TH recovery during the relaxation phases. Furthermore, the power law fitting is used to analyze the V TH shift under the positive program bias, indicating that a wide and easily accessible defects can exist in the IL and/or Si:HfO 2 since the smaller overdrive voltage dependence exponent (γ) is obtained in Si:HfO 2. Last, the smaller V TH shift/recovery in Gd:HfO 2 FeFETs can be attributed to a relatively tighter defect distribution, indicating that the dopants in the ferroelectric layer and the defects in IL and/or ferroelectric dielectric have to be carefully optimized to achieve the better V TH stability. • Si:HfO 2 FeFETs exhibit an obvious V TH recovery during the relaxation phases. • The power law fitting is used to analyze the V TH shift, indicating that a wide and easily accessible defects can exist in the IL and/or Si:HfO 2. • The smaller V TH shift/recovery in Gd:HfO 2 FeFETs indicates that the dopants and the defects have to be carefully optimized to achieve the better V TH stability. [ABSTRACT FROM AUTHOR]

This paper reports an extensive analysis of the trapping and reliability issues in AlGaN/GaN metal insulator semiconductor (MIS) high electron mobility transistors (HEMTs). The study was carried out on three sets of devices with different gate insulators, namely PEALD SiN, RTCVD SiN and ALD Al 2 O 3 . Based on combined dc, pulsed and transient measurements we demonstrate the following: (i) the material/deposition technique used for the gate dielectric can significantly influence the main dc parameters (threshold current, subthreshold slope, gate leakage) and the current collapse; and (ii) current collapse is mainly due to a threshold voltage shift, which is ascribed to the trapping of electrons at the gate insulator and/or at the AlGaN/insulator interface. The threshold voltage shift (induced by a given quiescent bias) is directly correlated to the leakage current injected from the gate; this demonstrates the importance of reducing gate leakage for improving the dynamic performance of the devices. (iii) Frequency-dependent capacitance–voltage (C–V) measurements demonstrate that optimized dielectric allow to lower the threshold-voltage hysteresis, the frequency dependent capacitance dispersion, and the conductive losses under forward-bias. (iv) The material/deposition technique has a significant impact on device robustness against gate positive bias stress. Time to failure is Weibull-distributed with a beta factor not significantly influenced by the properties of the gate insulator. The results presented within this paper provide an up-to-date overview of the main advantages and limitations of GaN-based MIS HEMTs for power applications, on the related characterization techniques and on the possible strategies for improving device performance and reliability. [ABSTRACT FROM AUTHOR]

Development of integration of different components with GaN-based technologies has been gaining traction in recently. Among these, diodes play important roles in GaN power ICs. For this work, a fabrication approach for integrating a Schottky barrier diode (SBD) with a p-GaN enhancement (E-mode) for 200 V switching application is demonstrated. The integrated SBD with 30-mm width shows a low forward voltage (V f) with more than 10A and 6A at V ac = 3 V at 25 °C and 150 °C, respectively. Additionally, the devices show a stable ON-resistance (R ON) (<20% increase) up to 200 V at 25 °C/150 °C under pulsed IV characterization and OFF-state stress, pointing out the robust stability for integrated GET-SBDs on a power p-GaN HEMT platform. [ABSTRACT FROM AUTHOR]

In this work we report on the three dominant trapping mechanisms affecting the dynamic performance of a double-heterostructure GaN-based MIS-HEMT grown on silicon substrate. In the OFF-state, with high drain voltage and pinched-off 2DEG, the dominant mechanism is the charge-trapping in the gate-drain access region caused by the transversal drain-to-substrate potential. This effect causes the dynamic increase of the ON-resistance, and is positively temperature-dependent, thus of great concern for high-temperature operation. In the SEMI-ON-state, due to the presence of high VDS and relatively high IDS, an additional trapping mechanism emerges, involving the injection of hot electrons from the 2DEG into trap states located in the GaN-buffer or in the AlGaN barrier. This mechanism, critical in hard-switching operations, affects both the ON-resistance and the VTH. Finally, when the gate is positively biased (gate overdrive state) trapping of electrons happens in the gate dielectric layer(s), leading to strong metastable VTH instabilities. [ABSTRACT FROM AUTHOR]

In this work, the ferroelectric characteristic of a 5 nm Hf0.5Zr0.5O2 (HZO) metal-ferroelectric-insulator-semiconductor (MFIS) device is enhanced through strained complementary metal oxide semiconductor (CMOS)-compatible TiN electrode engineering. Strained TiN top-layer electrodes with different nitrogen (N) concentrations are deposited by adjusting the sputtering process conditions. The TiN electrode with 18% N exhibits a compressive characteristic, which induces tensile stress in a 5 nm HZO film. A device with 18% N in TiN shows a higher remanent polarization (2Pr) and larger capacitance value than the compared sample, indicating that the strained TiN is promising for enhancing the ferroelectricity of sub-5 nm HZO devices. [ABSTRACT FROM AUTHOR]

In this work, we have demonstrated the wireless power transfer (WPT) system based on the pristine and irradiated E-mode GaN devices. The GaN device has been irradiated up to the 100 kGy dose under the γ-ray irradiation, showing the improved electrical characteristic, such as the drain current increase (~8.34%) and gate current decrease (~−7.79%). An off-state drain induced instability measurement shows the robust performance in pristine and irradiated GaN device. Noted that the irradiated device exhibits less ΔV TH , suggesting the device instability has been improved. Moreover, the wireless power transfer efficiency was evaluated by utilizing different load (20 Ω ~ 120 Ω) at V DS = 50 V and V GS = 4 V. The results indicate that the transfer efficiency of WPT by implementing the pristine and irradiated GaN device are similar. Furthermore, the output power of WPT using the irradiated GaN device becomes higher, which is mainly due to the improved drain current in irradiated GaN power devices. • Demonstration of the wireless power transfer (WPT) system based on the pristine and irradiated E-mode GaN devices. • The GaN device has been irradiated (γ-ray with 100kGy dose), showing the I D increase (~8.34%) and I G decrease (~-7.79%). • The wireless power transfer efficiency was evaluated by utilizing different loads (20 Ω~120 Ω) at V DS = 50V and V GS = 4V. • The transfer efficiency of WPT by implementing pristine and irradiated GaN device are similar. • Furthermore, the output power of WPT using the irradiated GaN device becomes higher. [ABSTRACT FROM AUTHOR]

In this work, we observe the distinct V TH characteristics in the Au-free gate-first processing p-GaN/AlGaN/GaN HEMTs with two commonly used passivation layers, i.e., SiN and SiO 2. The lower incorporated H was found in the p-GaN/AlGaN/GaN heterostructure with higher activation anneal temperature (i.e., 700 °C). Furthermore, Photoluminescence (PL) spectrum demonstrates a higher blue luminescence (BL) intensity after higher annealing treatment. The X-ray photoelectron spectroscopy (XPS) spectrum near valence band edge depicts a similar valence band maximum (VBM) characteristic, by means no impact on p-GaN surface bending by using distinct thermal treatment. The device with SiN shows a depletion-mode (D-mode) characteristic (V TH ~ -5 V) whereas the device with SiO 2 passivation exhibits an enhancement-mode (E -mode) characteristic (V TH ~ +0.7 V). Moreover, Transmission Line Model (TLM) devices are fabricated to investigate the effects of the passivation on two-dimensional electron gas (2DEG) in p-GaN/AlGaN/GaN stack. The results indicate that a low R sh is obtained while passivating device surface with SiN layer, suggesting that 2DEG is present, which is most probably due to an unfunctional p-GaN layer. The secondary ion mass spectrometry (SIMS) results indicate a high hydrogen intensity in the p-GaN/AlGaN/GaN stack with a SiN passivation layer. Thus, the p-GaN deactivation process that correlates to the formation of complex Mg H after SiN passivation is proposed to explain the D-mode characteristic in the device with a SiN passivation layer. [ABSTRACT FROM AUTHOR]

In this work, GaN-on-Si power Metal-Insulator-Semiconductor High Electron Mobility Transistors (MIS-HEMTs) are irradiated through different regimes of cumulative γ -ray irradiation, namely 1, 2, 3, 4, and 5 kGy for the first sample; 1, 3, and 5 kGy for the second sample; 1, 5, and 10 kGy for the third sample; and 1, 10, and 20 kGy for the fourth sample. After each irradiation dose, drain current (I D), threshold voltage (V Th), and gate leakage current (I g) are electrically characterized in all the samples. An improvement in I D with a shift in V Th is observed in all the samples, which saturates after a higher irradiation dose. X-ray photoelectron spectroscopy (XPS) analysis confirms creation of nitrogen vacancies that act as donor and improves the I D. No significant change in I g is observed except for an increase in noise in gate leakage current. Scanning electron microscopy (SEM) shows the Al-based metallization pad degrades due to formation of small cavities. Finally, energy dispersive X-ray (EDX) analysis confirms the formation of Al native oxides due to γ -ray irradiation. [ABSTRACT FROM AUTHOR]