Pulsed Large Signal RF Performance of Field-Plated Ga2O3 MOSFETs

Comparison between pulsed and CW large signal RF performance of field-plated β-Ga 2 O 3 MOSFETs has been reported. Reduced self-heating when pulse resulted in a power added efficiency of 12%, drain efficiency of 22.4%, output power density of 0.13 W/mm, and maximum gain up to 4.8 dB at 1 GHz for a 2-μm gate length device. Increased power dissipation for higher VDS and IDS resulted in a degradation in performance, which, thermal simulation showed, could be entirely explained by self-heating. Buffer and surface trapping contributions have been evaluated using gate and drain lag measurements, showing minimal impact on device performance. These results suggest that β-Ga 2 O 3 is a good candidate for future RF applications

Radiation hardness of b-Ga2O3 metal-oxide-semiconductor field-effect transistors against gamma-ray irradiation

The effects of ionizing radiation on b-Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) were investigated. A gamma-ray tolerance as high as 1.6 MGy(SiO2) was demonstratedfor the bulk Ga2O3 channel by virtue of weak radiation effects on the MOSFETs’ output current and threshold voltage. The MOSFETs remained functional with insignificant hysteresis in their transfercharacteristics after exposure to the maximum cumulative dose. Despite the intrinsic radiation hardness of Ga2O3, radiation-induced gate leakage and drain current dispersion ascribed respectively todielectric damage and interface charge trapping were found to limit the overall radiation hardness of these devices

Gamma-Ray Irradiation Effects on Ga2O3 MOSFETs

The high-voltage and high-temperature capabilities of Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) are expected to find applications in extreme radiation environments. This paper reports the first investigation into the effects of ionizing radiation on Ga2O3 MOSFETs. The devices remained fully functional after exposure to a cumulative gamma-ray (γ-ray) dose of 1 MGy(SiO2). High γ-ray tolerancewas demonstrated for the bulk Ga2O3 channel by virtue of the MOSFETs’ stable DC output characteristics against irradiation. Radiation-induced degradations in the gate insulation and surface passivation were found to limit the overall radiation resistance of these devices.第78回応用物理学会秋季学術講演

Design and Engineering of Ga2O3 MOSFETs for Next Generation Power Switches

β-Ga2O3 is being actively pursued for power switching and harsh environment electronics owing to its large bandgap of 4.5 eV and the availability of economical melt-grown native substrates. State-of-the-art Ga2O3 MOSFETs were realized on unintentionally-doped (UID) β-Ga2O3 (010) epilayers by employing Si-ion (Si+) implantation doping for the channel and ohmic contacts. Depletion-mode devices with a gate-connected field plate (FP) achieved a high off-state breakdown voltage of 755 V, a large drain current on/off ratio (ION/IOFF) of over 109, stable high temperature operation at 300°C, and dispersion-free pulsed output characteristics. Bulk Ga2O3 exhibited high gamma-ray tolerance by virtue of the MOSFETs’stable DC characteristics against irradiation, while radiation-induced dielectric damage and interface trap generation limited the overall radiation hardness of these devices. A large thermal resistance of 48 mm·K/W extracted under room temperature device operation highlights the pertinence of thermal management to the performance and reliability of Ga2O3 transistors. Low residual carrier density in UID Ga2O3 enabled full channel depletion at zero gate bias for a positive threshold voltage in Si+-implanted enhancement-mode β-Ga2O3 (010) MOSFETs with low series resistance. Despite strong charge trapping effects associated with an unoptimized gate dielectric, a decent ION of 1.4 mA/mm and large ION/IOFF near 106 were achieved.The Tenth International Conference on the Science and Technology for Advanced Ceramics (STAC-10

Radiation Hardness of Ga2O3 MOSFETs against Gamma-Ray Irradiation

Gallium oxide (Ga2O3) is attractive for power devices owing to its wide bandgap of 4.5 eV and the availability of economical device-quality native substrates. Recent research on Ga2O3 Schottky barrier diodes and field-effect transistors (FETs) has seen rapid progress. An unexplored area of immense interest is the radiation tolerance of these devices, whose high-voltage and high-temperature capabilities are expected to find applications in extreme radiation environments such as space and nuclear facilities that impose stringent reliability requirements to ensure stable operations. This paper reports the first investigation into the effects of ionizing radiation on Ga2O3 metal oxide-semiconductor FETs (MOSFETs). A gamma-ray (γ-ray) tolerance as high as 230 kGy(SiO2) was demonstrated for the bulk Ga2O3 channel by virtue of the MOSFETs’ stable on-current, on-resistance (RON), and threshold voltage (VT). Radiation-induced degradations in the gate insulation and surface passivation, which could be attributed to dielectric damage and interface trap generation, were found to limit the overall radiation resistance of these devices.75th Device Research Conference (DRC

Reflections on the State of Ultra-Wide-Bandgap Ga2O3 MOSFETs

Gallium oxide (Ga2O3) is an emerging ultra-wide-bandgap (4.5–4.9 eV) semiconductor for high power and high voltage electronics with potential applications in harsh environments. Since the first report of a Ga2O3 field-effect transistor (FET) in 2012, Ga2O3 power devices have undergone tremendous technological advancement. This talk reviews the progress we have made and the lessons we have learnt on both lateral and vertical Ga2O3 metal-oxide-semiconductor (MOS) FETs. Future development directions will also be discussed.20th Workshop on Dielectrics in Microelectronic

Ga2O3 power transistors: The promise, the reality, and future directions

The pursuit of Ga2O3 as an ultra-wide-bandgap (4.5–4.9 eV) semiconductor for next-generation power-switching and harsh-environment electronics has catalyzed the rapid development ofGa2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) in recent years. Field-plated lateral depletion-mode devices demonstrated a high off-state breakdown voltage of 755 V, a large on/off current ratio of over nine orders of magnitude, dispersion-free output characteristics, stable high temperature operation, and strong gamma-ray tolerance. Enhancement-mode operation with a six-order-of-magnitude on/off current ratio was enabled by an unintentionally-doped epitaxial Ga2O3 channel that was fully depleted at zero gate bias due to a low background carrier density. Planar-gate vertical Ga2O3 MOSFETs, wherein a current blocking layer provided electrical isolation between source and drain except at an aperture opening through which drain current was conducted, demonstrated successful transistor action. Advanced transistor architectures, notably normally-off vertical devices, will further enhance the impact of Ga2O3 power electronics.he 2018 E-MRS Fall Meetin