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A GaN Schottky barrier diode (SBD) on SiC for frequency doubler applications was fabricated with a N−/N+ GaN stack of 200 nm/1500 nm in thickness and 5 × 1017 cm-3/8 × 1018 cm-3 in doping densities, respectively. A cut-off frequency of 459 GHz at zero bias and reverse breakdown voltage of 15.4 V were obtained. A quartz glass circuit with flip-chip-mounted GaN SBDs was inserted between split-waveguide blocks to form a balanced frequency doubler. When driven with 2 W input power in pulsed mode, measured output power was 200–244 mW from 177–183 GHz with efficiency 9.5-11.8%. [ABSTRACT FROM AUTHOR]

In this work, we have demonstrated high-performance lateral $\beta $ -Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) with state-of-art power figure-of-merit (P-FOM) and breakdown voltage (BV) by adopting a T-shape gate field-plate and source connected field-plate structures. Depletion-mode (D-mode) $\beta $ -Ga2O3 MOSFETs with gate-to-drain distance ($\text{L}_{\sf GD}$) of $4.8~\mu \text{m}$ /17.8 $\mu \text{m}$ demonstrate a BV of 1.4 kV/2.9 kV and specific ON-resistance ($\text{R}_{ \mathrm{\scriptscriptstyle ON}, {\sf sp}}$) of 7.08 $\text{m}\Omega \cdot $ cm2/46.2 $\text{m}\Omega \cdot $ cm2, respectively, yielding a high P-FOM of 277 MW/cm2 and averaged electrical field of 2.9 MV/cm for the device with $\text{L}_{\sf GD} = {\sf 4.8}\,\, \mu \text{m}$. To the best of all the authors’ knowledge, this P-FOM of 277 MW/cm2 and BV = 2.9 kV are the highest values among all the lateral D-mode $\beta $ -Ga2O3 MOSFETs. Combined with negligible gate pulsed and drain pulsed current collapse and drain current on/off ratio of 109, these $\beta $ -Ga2O3 MOSFETs show a great potential for future power electronic applications. [ABSTRACT FROM AUTHOR]

Herein, high‐performance enhancement‐mode (E‐mode) β‐Ga2O3 metal‐oxide‐semiconductor field‐effect transistors (MOSFETs) are achieved on Si‐doped homoepitaxial films. Oxygen annealing (OA) treatment under the gate region is used to effectively exhaust the channel electron, resulting in the normally off operation of the device. The threshold voltage, defined as that at the drain current of 0.1 mA mm−1, for the fabricated device is extracted to be 4.1 V. Moreover, double source‐connected field plates are used to suppress the peak electric fields in both Ga2O3 channel and SiNx passivation layer. The fabricated β‐Ga2O3 MOSFETs with gate‐to‐drain distance (Lgd) of 17 μm exhibit a record high breakdown voltage over 3000 V. It is shown that the OA treatment is a new way to obtain high‐performance E‐mode β‐Ga2O3 power MOSFETs. [ABSTRACT FROM AUTHOR]

In this letter, a high-performance ($\overline {{2}} 01$) $\beta $ -Ga2O3 vertical Schottky Barrier Diode (SBD) with a thermally oxidized termination is reported. A novel edge termination at the Schottky contact edge is formed by using thermal oxidation treatment, which reduces the electron concentration and effectively suppresses the peak electric field. By using a thermal oxidation termination, the breakdown voltage (${V}_{\text {br}}$) of $\beta $ -Ga2O3 SBD increases from 380 V to 940 V, and the specific on-resistance (${R}_{\text {on,sp}}$) just increases from 2.9 $\text{m}\Omega \cdot $ cm2 to 3.0 $\text{m}\Omega \cdot $ cm2. Our device demonstrates a power figure of merit (${V}_{\text {br}}^{{2}}/{R}_{\text {on,sp}})$ as high as 295 MW/cm2. These results indicate that the thermally oxidized termination shows a new way to improve the breakdown characteristics of $\beta $ -Ga2O3 SBD. [ABSTRACT FROM AUTHOR]

In this letter, high-uniformity $8\times 8$ arrays of 4H-SiC ultraviolet (UV) avalanche photodiode (APD) are reported. In order to improve the detectivity, large active area ($300~\mu \text{m}$ diameter) was designed for APD pixels. Thick SiNx dielectric deposited by plasma enhanced chemical vapor deposition (PECVD) was adopted as insulator and passivation layer to suppress the reverse leakage current and premature breakdown. Despite the large active area, a high yield of 97% is achieved for the pixels in the 4H-SiC APD array. At room temperature, the pixels exhibit a high gain of over 105, a maximum quantum efficiency of larger than 68% @ 282 nm and an excellent UV/visible rejection ratio of 104. In addition, temperature-stable avalanche breakdown voltage with a positive coefficient of 8 mV/°C is obtained. Furthermore, the APD array shows a high uniformity of breakdown voltage with a standard deviation of 0.1 V for all the 64 pixels, and the dark currents at 95% of breakdown voltage are as low as ~1 nA except for two pixels. The performance improvements indicate a new milestone for 4H-SiC APD arrays in UV imaging applications. [ABSTRACT FROM AUTHOR]

In this letter, source-field-plated $\beta $ -Ga2O3 MOSFETs are fabricated on Si-doped homoepitaxial film on (010) Fe-doped semi-insulating $\beta $ -Ga2O3 substrate. Ohmic contact resistance (${R}_{\textsf {c}}$) between metal- and ion-implanted source/drain layer of $1.0~\Omega ~\cdot $ mm is obtained by employing the Si-ion implantation. The fabricated source-field-plated $\beta $ -Ga2O3 MOSFETs with source-to-drain distance (${L}_{\textsf {sd}}$) of 11 and $18~\mu \text{m}$ present high-saturation drain current (${I}_{\textsf {ds,sat}}$) of 267 and 222 mA/mm with low ${R}_{\textsf {on,sp}}$ of 4.57 and 11.7 $\text{m}\Omega ~\cdot $ cm2, respectively. The drain extension in the source-field plate effectively suppresses the peak electric field and improves the breakdown voltage greatly. The destructive breakdown voltages (${V}_{\textsf {br}}$) are measured to be 480 and 680 V for the devices with ${L}_{\textsf {sd}}$ of 11 and 18 $\mu \text{m}$ , respectively. Most of all, the power figure of merit (${V}_{\textsf {br}}^{\textsf {2}}/{R}_{\textsf {on,sp}})$ is as high as 50.4 MW/cm2, which is the highest value among any $\beta $ -Ga2O3 MOSFETs ever reported. [ABSTRACT FROM AUTHOR]

In this Letter, high-uniformity 1 × 64 linear arrays of 4H-SiC avalanche photodiode (APD) are reported for ultraviolet detection. Multi-cycle inductively coupled plasma dry etching was adopted for the bevelled mesa formation, during which the wafers were rotated with a small angle for each cycle to suppress the process variation. As a result, a high pixel yield of 100% and a high-uniformity breakdown voltage with a fluctuation of smaller than 0.5 V are achieved for the fabricated 1 × 64 4H-SiC APD linear arrays, which is a great improvement for 4H-SiC APD arrays. Moreover, the dark currents at 95% of breakdown voltage are below 1 nA for all the 64 pixels. Besides, the pixels in the array show a multiplication gain of larger than 106 and a peak responsivity of 0.12 A/W at 285 nm (corresponding to a maximum quantum efficiency of 52%) at room temperature. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate a 253% improvement in the off-state breakdown voltage (BV) of the lattice-matched \In0.17\Al0.83 \N/GaN high-electron-mobility transistors (HEMTs) by using a new Schottky-contact technology. Based on this concept, the Schottky-source/drain and Schottky-source (SS) InAlN/GaN HEMTs are proposed. The proposed InAlN/GaN HEMTs with an LGD of 15 \mu\m showed a three-terminal BV of more than 600 V, while the conventional InAlN/GaN HEMTs of the same geometry showed a maximum BV of 184 V. Without using any field plate, the BV of 650 V was measured in the SS InAlN/GaN HEMTs with LGD = \15\ \mu\m, which is the highest BV ever achieved on InAlN/GaN HEMT. The corresponding specific on-resistance (Rsp, on) is as low as 3.4 \m\Omega \cdot \cm^2. A BV of 118 V was also obtained in SS InAlN/GaN HEMTs with LGD = \1\ \mu\m, which is the highest BV in GaN-based HEMTs featuring such a short LGD with GaN buffer. The improvement of the BV relies on the effective suppression of source carrier injection into the GaN buffer under the SS due to the smooth metal morphology and elimination of metal spikes in the Schottky metallization. [ABSTRACT FROM AUTHOR]