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This paper presents the fabrication procedure of TiO2 passivated field plate Schottky diode and gives a comparison of Ni/Au/n-GaN Schottky barrier diodes without field plate and with field plate of varying diameters from 50 to 300 µm. The influence of field oxide (TiO2) on the leakage current of Ni/Au/n-GaN Schottky diode was investigated. This suggests that the TiO2 passivated structure reduces the reverse leakage current of Ni/Au/n-GaN Schottky diode. Also, the reverse leakage current of Ni/Au/n-GaN Schottky diodes decreases as the field plate length increases. The temperature-dependent electrical characteristics of TiO2 passivated field plate Ni/Au/n-GaN Schottky diodes have shown an increase of barrier height within the temperature range 300…475 K.

The short circuit (SC) behavior of a newly developed GaN-HEMT/SiC-JFET cascode device is investigated in this work. The reverse leakage current through the drain-side PN junction ( IR ) of the SiC JFET under SC conditions is measured simultaneously during the SC event. IR of the SiC JFET increases to 6.4 A at the end of a 5-μs nondestructive SC pulse. The increase of IR during the SC pulse induces a turning point in the SC current waveform and a dramatic negative threshold voltage shift (>30 V) in the SiC JEFT, resulting in high transient drain-to-source voltage in the GaN HEMT. The underlying mechanism is associated with the increase of local potential in the P-type layer of the SiC JFET with inevitable spread resistance ( R SPD). It is suggested that reducing R SPD can improve SC capability and high IR should be considered in SC failure mechanism analysis and the design of external gate resistance of the SiC JFET.

This article presents a fully energy-autonomous temperature-to-time converter (TTC), entirely powered up by a triboelectric nanogenerator (TENG) for biomedical applications. Existing sensing systems either consume too much power to be sustained by energy harvesting or have poor accuracy. Also, the harvesting of low-frequency energy input has been challenging due to high reverse leakage of a rectifier. The proposed dynamic leakage suppression full-bridge rectifier (DLS-FBR) reduces the reverse leakage current by more than 1000 $\times $ , enabling harvesting from sparse and sporadic energy sources; this enables the TTC to function with a TENG as the sole power source operating at $\mu \text{m}$ 1P6M CMOS technology, consuming 0.14 pJ/conversion with 0.014-ms conversion time.

In this letter, the ultrafast reverse recovery β -Ga2O3 Schottky barrier diode (SBD) with improved breakdown voltage is proposed and investigated experimentally. It features the compound termination, consisting of air space field plate and thermal oxidation terminal. The compound termination not only reduces high-density interface states at the dielectric/Ga2O3 interface and the electron concentration in the oxidation terminal, but also modulates the electric-field distribution and suppresses the peak electric-field at the bottom of anode. Therefore, the reverse leakage current is suppressed as well as the reverse recovery and breakdown characteristics are improved effectively. The Ga2O3 SBDs with the diameter of 1000 μm obtain ultrashort reverse recovery time of 7.5 ns and ultralow reverse recovery charge of 1.0 nC at di / dt = 50 A/μs with its breakdown voltage up to 400 V, maintaining good rectification characteristics. The temperature-dependences of both forward conduction and reverse recovery characteristics are discussed in temperature range from 300 to 500 K. The results prove that the superior electronics performance of the β -Ga2O3 SBDs with good electronics thermal tolerance can overcome the low thermal conductivity of β -Ga2O3 to a certain extent. The fabricated β -Ga2O3 SBDs have great potential for high power and high-frequency applications.

In the modeling of PV modules under shading and low illumination, a complete description of reverse bias behavior at the cell level is critical to understanding module response. This is particularly important when dealing with high voltage configurations such as tandem and shingled modules. Current simulation studies often do not account for the effects of incident light when dealing with operating voltages approaching cell breakdown. In this article, we investigate the illumination dependence of leakage current at the onset of breakdown in crystalline silicon solar cells. A study of the most popular cell technologies in the market today reveals a light induced effect under reverse bias that is prominent for p-type and small for n-type cells. Additionally, this effect is found to be larger in mono c-Si than multi c-Si cells. Because this phenomenon is not captured in current breakdown models such as Bishop's equation, we propose a split-cell model to describe partial shading in p-type cells. The outlined approach divides the cell into two parallel regions and is advantageous for its procedural simplicity as well as its ability to generalize effects from complex shading profiles.

We successfully fabricated the Al0.58Ga0.42N-based solar-blind ultraviolet (UV) Schottky type photodetectors (PDs). The crystalline quality, morphology and dislocation information of the Al0.58Ga0.42N epitaxial layer have been obtained by detailed characterizations of high-resolution X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscope (TEM). In addition, the responsivity of the PD with cutoff wavelength of 260 nm is 0.15A/W at −5V and 0.12 A/W at 5 V, respectively. Detailed carrier transport models are explored to analyze the I-V-T characteristics measured between 300 and 425 K, in order to provide more information for analyzing the reverse leakage mechanisms in the Al0.58Ga0.42N solar-blind PD. It is convincingly demonstrated that thermionic-field emission and Poole–Frenkel emission can accurately describe the low-bias I-V characteristics and the high-bias I-V characteristics, respectively.

The effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diodes were studied. We fabricated the PIN rectifier diodes with different initial oxygen concentrations, and analyzed the electrical properties, anisotropic preferred etching by means of optical microscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. It is pointed out that the reverse leakage current increases exponentially with the increasing initial oxygen concentration. Furtherly, we researched and analyzed the mechanism of the effects of initial oxygen concentration on the reverse leakage current of PIN rectifier diode. It is shown that the oxygen precipitations present in an “S” curve with increasing initial oxygen concentration after high temperature diffusion. The main reason is that the nucleation and growth of oxygen precipitation at high temperature induce bulk oxidation-induced defects (B-OSF), which are mainly dislocations, and a small amount of rod stacking faults. The density of B-OSF increases with the increasing initial oxygen concentration. The existence of B-OSF has great effects on the reverse leakage current of PIN rectifier diode.

In this article, a $\beta $ -Ga2O3 metal-interlayer-semiconductor Schottky barrier diode (MIS-SBD) using Al-reacted aluminum oxide as the interlayer is demonstrated for the first time and compared with conventional metal-semiconductor (MS) Schottky barrier diode (SBD). The aluminum oxide is formed by sputtering a thin Al layer on Ga2O3 substrate and then annealed in O2 at 300 °C. With the insertion of Al-reacted interlayer, the SBD subthreshold swing (SS) is significantly improved to 61 mV/dec with an average current range of >6 orders. Example of atomic layer deposited (ALD) Al2O3 as the interlayer is also fabricated and characterized. ${J}$ – ${V}$ study corrected by Gaussian distribution model shows that all the samples statistically exhibit similar mean barrier heights (BHs). This indicates that the interlayer hardly affects the electrostatic field and band bending as experienced by carrier injections. ${C}$ – ${V}$ study provides different BH results in different sample setups. The result proves that Al-reacted interfacial layer helps eliminate interface degradation as compared with ALD Al2O3. Overall, MIS-SBD by Al-reaction method exhibits improved SS, reduced reverse leakage current ( ${I}_{0}$ ), low ideality factor, good ON-OFF ratio ( $> 10^{9}$ ), and minimized interface charges as compared with its respective counterparts. The result of this article serves as a promising interface engineering technique for Ga2O3-based SBD designs.

Dopant segregation (DS) technique has been extensively employed to tune Schottky barrier heights (SBHs) of NiSi/Si diodes, either leading to reduced specific contact resistivity ( $\rho _{\text {c}}$ ) in source/drain (S/D) Ohmic contacts, or enhanced current drivability in Schottky barrier S/D MOSFET (SB-MOSFET) where metallic NiSi is employed as S/D. A capacitance–voltage ( ${C}$ – ${V}$ ) method is usually adopted to reliably extract the SBHs of NiSi/Si for investigating the effectiveness of such a DS technique. In order to avoid large reverse leakage current which rules out the possibility of SBHs extraction during ${C}$ – ${V}$ measurements, dopants with opposite polarity to that in epitaxial Si substrate segregate at the NiSi/Si interface, for instance, boron DS (B DS) for NiSi/n-Si and arsenic DS (As DS) for NiSi/p-Si. This, however, raises one critical question, i.e., NiSi/p+-Si (B DS)/n-Si and NiSi/n+-Si (As DS)/p-Si are p-n or Schottky junctions. In this work, a dedicated circuit is devised to distinguish the type of as-fabricated NiSi/Si diodes with DS based on different switching mechanisms between p-n and Schottky junctions.

High-performance AlGaN/GaN lateral Schottky barrier diodes (SBDs) with recess structure and dual metal nitride anodes were demonstrated. With high work-function and nonrecess structure, a NiN anode enhances the breakdown voltage (BV), while a TiN anode reduces the turn-on voltage ( ${V}_{ \mathrm{\scriptscriptstyle ON}}$ ) due to its low work-function and contact to the two-dimensional electron gas (2DEG) layer directly on a recess structure. As the length of the NiN anode ( ${L}_{r}$ ) on the nonrecess region decreases from 75 to 3 $\mu \text{m}$ , ${V}_{ \mathrm{\scriptscriptstyle ON}}$ is reduced from 0.56 to 0.30 V, while the reverse leakage current slightly increases from ${3} \times {10}^{-{4}}$ to ${2} \times {10}^{-{3}}$ A/cm2 at the bias of −10 V. The lateral AlGaN/GaN SBD with a ${L}_{r}$ of 3 $\mu \text{m}$ at a distance of cathode–anode ( ${L}_{\text {AC}}$ ) of 20 $\mu \text{m}$ achieves a high BV of 1.62 kV, an ultralow ${V}_{ \mathrm{\scriptscriptstyle ON}}$ of 0.30 V and a small capacitance of 6.0 pF at zero bias with little degradation on ON-resistance, indicating superior potential application in high-frequency and high-power devices.

The change in the electrical properties of 4H-SiC Schottky barrier diodes (SBDs) irradiated by 6 MeV Au ions at low temperature (LT) is investigated. The SBDs are characterized by current–voltage (I-V) and capacitance–voltage (C-V). The SRIM software is used to calculate the Au ion transportation process. The experimental results indicate that the ideality factor (n) and the reverse leakage current (IR) increase, and Schottky barrier height (SBH) decreases with the increase in fluence. It is found that series resistance (RS) and effective impurity concentration (ND) are recovered at 5 × 1015 ions/cm2. Calculation results show that the mental layer can prevent most of the Au ions, while the secondary particles will enter the SiC layer. Therefore, these results demonstrate that the secondary particles induce many defects at the metal-SiC interface and the SiC epitaxial layer after LT heavy ion (HI) irradiation.

We propose self-rectifying resistive random access memory (RRAM) synapse to prevent reverse leakage current problem which occurs when RRAM is integrated with integrate and fire (IF) circuit in spiking neural network (SNN). Ni/W/SiN x /n-Si RRAM was fabricated by varying the bottom electrode (BE) doping concentration and their rectifying characteristics were analyzed. Low BE doping concentration device showed self-rectifying characteristics without any additional selector or diode device. Furthermore, hardware-based system-level simulation was conducted to evaluate the effect of self-rectifying RRAM synapse on MNIST classification accuracy. About 93.34% accuracy was obtained using the proposed RRAM.

In this article, a 15-W quadruple-mode reconfigurable wireless power-receiving unit with high efficiency for Inductive coupling and magnetic resonance-based standards, such as wireless power consortium (WPC), power matters alliance (PMA), alliance for wireless power (A4WP), and magnetic secure transmission (MST) applications is proposed. Quadruple-mode gate controller(QMGC) is proposed in quadruple-mode synchronous rectifier to manage sizes of core and drivers which results in maximum power conversion efficiency (PCE) for each mode based on conduction and switching losses. In QMGC, switchable zero voltage and current sensing block is proposed for WPC/PMA to maximize PCE regardless of load current variations. For A4WP mode, a digitally controlled delay adjustment block is adapted to minimize power consumption while compensating for delay which results in reverse leakage current and power loss. Finally, for MST mode, low power TX (LPTX) block is implemented to minimize current consumption so that burden on battery can be minimized. A high-resolution current sensor is proposed in low-drop out regulator to sense current for overcurrent limit and overcurrent protection. The measured PCE of proposed system at 15 W are 95.3% and 92.3% for WPC/PMA and A4WP mode, respectively. For MST, power consumption is reduced to 35% courtesy LPTX block.

This work reports a $\beta $ -Ga2O3 double-barrier Schottky barrier diode (DBSBD) with both low turn-on voltage and low reverse leakage current by using Ni and PtOx as the anode electrode. The barrier height of PtOx-based diode can be effectively modulated from 1.26 to 1.62 eV by adjusting oxygen pressure during sputtering processes. Combining the maximum work function of PtOx electrode with the optimization of the electrode ratio of Ni and PtOx, the DBSBD with an electrode diameter ratio of $\text{D}_{\text {Ni}} /\text{D}_{\text {PtOx}}= {75}/{150} \mu \text{m}$ not only exhibits a high forward current of 470.9 A/cm2 (at 3.5 V), a low on-resistance of 4.1 $\text{m}\Omega ~\cdot $ cm2 and a low turn-on voltage of 1.13 V, but also possesses a relatively low reverse leakage current of ${1.2}\times {10}^{-{7}}$ A/cm2 (at −100 V), which is more than one order of magnitude lower than that of the Ni-SBD. Silvaco TCAD simulation reveals that such optimization can be attributed to the suppression of edge leakage current due to the double-barrier contact. Therefore, the strategy of double-barrier design can balance the forward and reverse characteristics in SBD, providing a new device structure for advanced power electronics.

This paper demonstrates the electrical and current transport properties of prepared Ti/α-amylase/p-InP metal/polymer/semiconductor (MPS) junction by current–voltage (I–V) approach. The microstructure of the fabricated MPS junction is confirmed by transmission electron microcopy (TEM) measurement. The MPS junction exhibited a good rectification nature over the Ti/p-InP metal/semiconductor (MS) junction. The derived barrier height (BH) of MPS junction (0.78 eV) is higher than the MS junction (0.70 eV), that indicates the BH is influenced by the polymer layer. The BH is extracted by the I–V, Z(V)–Vd plot, Cheung’s function, α(V)–V plot, Norde method and Ψs–V plot and found the values are comparable with one another, which indicates their steadiness and validity. The estimated interface state density (NSS) of the MPS junction is less than the MS junction, suggesting that the α-amylase layer decreased the NSS value. The forward log (I)–log (V) plot of the MS and MPS junctions reveals the ohmic nature at lower-bias region and space-charge-limited conduction at higher-bias region. Results reveal that the reverse leakage current conduction mechanism of the MS and MPS junctions is governed by Poole–Frenkel emission in lower-bias region, whereas, at higher bias region, Schottky emission is dominant current conduction mechanism. These exploration results establish that the α-amylase polymer layer is potential for use in organic–inorganic devices.

Fabrication of dual-barrier planar (DBP) structure diamond Schottky barrier diodes (SBDs) with only Ni Schottky contact was carried out by rapid thermal annealing. Ni/Au narrow stripes were first patterned on $\text{p}^{-}$ layer and annealed at 550 °C to decrease Schottky barrier height and form low barrier contact. Then, Ni/Au Schottky electrodes were deposited on the window area between stripes to serve as high barrier contact. Ti/Pt/Au ohmic contact was formed on the back side of $\text{p}^{+}$ diamond substrate. The fabricated DBP structure SBDs exhibit low forward voltage drops compared with single high barrier diode, and reverse leakage current densities of two to three orders of magnitude smaller than that of single low barrier diode. The influence of stripes area proportion on device properties was investigated and the barrier height can be adjusted by changing dual-barrier ratio. This new device structure displays a small power dissipation of 0.54 W/cm2, which is a promising technology for high power diamond diodes.

This paper presents an overall optimization procedure and the electrical performances of 1.2 kV/10 A 4H-SiC junction barrier Schottky (JBS) diodes with high current density. To achieve high current density, the epi-layer, the design parameters for active region including p-grid width and cell pitch, and the field limiting ring for edge termination were optimized with analytic calculation to estimate forward electrical performances and with Silvaco atlas™ simulator to estimate reverse electrical performances. Based on the systematic design, the JBS diodes were fabricated and electrically characterized. The experimental results showed that the breakdown voltage (BV) of JBS diode was significantly sensitive to field limiting ring (FLR) space and that the JBS diode with the ratio of pure Schottky contact area to total active area of 0.75 and the FLR space of 1.25 μm had optimum electrical performances such as a forward current density of 370 A/cm2, a reverse leakage current below 20 μA at the reverse anode voltage of 1.2 kV, and the BV of 1400 V. These were in coincidence with the simulation results within 10% error.

We analyzed current conduction mechanisms (CCMs) of the (Au/Ti)/Al2O3/n-GaAs (MIS) type SBDs in the wide temperature range (80-380 K) by 30 K steps using reverse bias current-voltage (I-R-V-R) characteristics. In general, the values of barrier-height (BH) obtained from the forward bias current-voltage (I-F-V-F) and reverse bias current-voltage (I-R-V-R) characteristics increase with increasing temperature and this change is in-agreement with the reported negative-temperature coefficient bandgap of semiconductor (alpha = Delta Eg/Delta T) or BH for ideal SDs. However, the change in BH at lower temperatures becomes more pronounced. The value of BH obtained from the I-R-V-R data is lower than that obtained from I-F-V-F especially under room temperatures. The necessary barrier height (phi(t)) for electron emission from the trap state was obtained from the ln (I-R) - E-0.5, (E = V-R/d), plot as 1.25 eV to (at 80 K) 0.91 eV (at 380 K), respectively. This change in the phi(t) with temperature is in agreement with the reported alpha value of the Eg for GaAs. The reverse leakage current mechanism in this study was assessd for various temperatures using Schottky emission (SE), Poole-Frenkel emission (PFE), Trap-Assisted Tunneling (TAT), and ohmic conduction mechanisms. The evaluation of the I-R-V-R characteristics shows that the ohmic and TAT are the most dominant conduction mechanisms rather than others.

Surface treatment is quite vital to reduce the reverse leakage current and improve the current On–Off ratio of gallium nitride (GaN) quasi-vertical Schottky barrier diode (SBD). In this work, we report a new nondestructive low temperature supercritical CO2 fluid (SCF) nitridation technology to treat the surface of GaN and substantially reduce the leakage current of GaN quasi-vertical SBD. The X-ray photoelectron spectroscopy (XPS) reveals the increased nitriding degree and oxygen doping degree in the form of GaO x after the SCF process results in the leakage performance improvement. As a result, the defects at metal/semiconductor interface are passivated. Also, because of NH-2 and OH− generated from the SCF process, the surface peak electric field of n−GaN decreases, and thus the breakdown voltage is enhanced. The reverse leakage current density is reduced by more than three orders of magnitude from $3.7\times 10^{-{6}}$ to $3.52\times 10^{-{9}}$ A/cm2 (at −3 V) and the ON-/ OFF-current ratio is improved by three orders from $8\times 10^{{7}}$ to $5.74\times 10^{{10}}$ .

A Ka -band AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistor (MIS-HEMT) with SiN gate dielectric grown by plasma-enhanced atomic layer deposition (PEALD) is demonstrated. The gate reverse leakage current in a controlled HEMT is reduced by about three orders of magnitude by the PEALD-SiN, contributing to an improved breakdown voltage of 92.5 V (source–drain separation of $2.0~\mu \text{m}$ ) in the fabricated MIS-HEMTs. The MIS-HEMTs also feature small threshold voltage hysteresis in dc transfer and capacitance–voltage characterizations, suggesting a good PEALD-SiN/AlGaN interface. The fabricated MIS-HEMTs deliver a high output power density of 7.16 W/mm and a peak power-added efficiency of 60.3%, respectively, at ${V}_{\text {DS}} =30$ V and ${V}_{\text {DS}} =10$ V in pulse mode at 28 GHz. PEALD-SiN could be a compelling gate dielectric for fabrication of high-power and high-efficiency MIS-HEMTs.

Carbon impurities are common defects in monocrystalline silicon and have negative effects on the electrical performance of electronic devices. In the present work, the effects of carbon impurities in monocrystalline silicon on the electrical properties of PIN rectifier diodes with different carbon concentrations were investigated by electrical performance tests, anisotropic preferential etching, Fouriertransform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). It was found that with the increasing carbon concentration, the reverse leakage current (IR) increased rapidly, the time of reverse recovery (TRR) and the ratio of the average reverse withstand voltage to the theoretical value decreased rapidly, and the forward voltage drop (Vf ) increased significantly. Further, with the rising carbon concentration, bulk oxidation-induced defects (B-OSF) changed from dislocation-dominated to stacking fault-dominated and the stacking fault length increased gradually. [Ci-Oi] carbon centers of interstitial carbon and interstitial oxygen with a wide absorption band were detected by FTIR. The existence of stacking dislocation defects and carbon-oxygen complexes [Ci-Oi] was confirmed by TEM and EDS. It was pointed out that substitutional carbon (Cs) captured interstitial silicon atoms, changed into interstitial carbon (Ci) in the silicon substrate, and formed [Ci-Oi] complexes of interstitial carbon and interstitial oxygen after high-temperature diffusion, and these complexes acted as heterogeneous nucleation centers to promote the formation and growth of oxygen precipitation. Due to the volume strain energy, interstitial silicon atoms and dislocations were continuously released to promote oxygen atoms during the growth process of carbon-oxygen complexes. The formation and growth of B-OSF defects caused the “impurity piercing pipe”effect. These defects acted as defect recombination centers and deteriorated the electrical performance of the PIN rectifier diodes.

We determined the optical and electrical characteristics of GaN-based, ultraviolet micro light emitting diodes (microLEDs). Such microLEDs are essential to next-generation high-resolution micro-displays. Square-shaped microLEDs of different sizes (side lengths: 5-50 μm) were designed. The peak emission wavelength of these devices shifted

This letter reports on the suppression of reverse leakage current ( ${I} _{r}$ ) in $\beta $ -Ga2O3 Schottky barrier diodes (SBDs) through Schottky barrier modification by a low power CF4-plasma treatment prior to Schottky metal deposition. Revealed by an x-ray photoelectron spectroscopy (XPS) analysis, the fluorine-plasma treatment brought an incorporation of fluorine ions and depletion of silicon donors in the near surface region of the $\beta $ -Ga2O3, and thus raised its surface potential by around 0.14 eV. Furthermore, insulating GaF x was likely created at the Schottky interface. Attributed to the fluorine-plasma- modified Schottky barrier, a reduced ${I} _{\mathbf {r}}$ by around four orders of magnitude and enhanced blocking voltage ( ${V} _{{block}}$ ) from 150 V to 470 V at ${I} _{r} = 100\mu $ A/cm2 have been achieved without degrading the forward characteristics. Different from the untreated device whose ${I} _{r}$ was purely governed by the thermionic field emission (TFE), the fluorine-plasma-treated SBD showed a greatly suppressed TFE-current until a space-charge limited current (SCLC) started to dominate at around −500 V.

In this paper, we pose reverse leakage current issue which occurs when resistive random access memory (RRAM) is used as synapse for spiking neural networks (SNNs). To prevent this problem, 1 diode-1 RRAM (1D1R) synapse is suggested and simulated to examine their current rectifying chracteristics, Furthermore, high density of 1 K 3D 1D1R synapse array structure and its process flow are proposed.