A5070270057- Ga2O3 and related materials
- ZnO doping and properties
- Advanced Photocatalysis Techniques
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Induction Heating and Inverter Technology
- Silicon Carbide Semiconductor Technologies
- Microwave Engineering and Waveguides
- Luminescence Properties of Advanced Materials
- GaN-based semiconductor devices and materials
- Acoustic Wave Resonator Technologies
Wright-Patterson Air Force Base
2019-2025
United States Air Force Research Laboratory
2017-2024
U.S. Air Force Research Laboratory Sensors Directorate
2019-2024
University of California, Santa Barbara
2022-2024
Sensors (United States)
2022-2023
University of California System
2022
We report enhancement-mode <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (BGO) MOSFETs on a Si-doped homoepitaxial channel grown by molecular beam epitaxy. A gate recess process is used to partially remove the epitaxial under 1- notation="LaTeX">$\mu...
Abstract Beta phase Gallium Oxide (BGO) is an emerging ultra-wide bandgap semiconductor with disruptive potential for ultra-low power loss, high-efficiency applications. The critical field strength the key enabling material parameter of BGO which allows sub-micrometer lateral transistor geometry. This property combined ion-implantation technology and large area native substrates result in exceptionally low conduction losses, faster switching frequency even radio power. We present a review...
We demonstrate Schottky barrier engineering using PtOx/thin Pt contacts combined with edge termination a high permittivity dielectric (ZrO2) field-plate for high-voltage vertical β-Ga2O3 diodes. A systematic study of baseline bare Pt/β-Ga2O3, and PtOx/β-Ga2O3 diode characteristics was performed, which revealed that the Pt/β-Ga2O3 contact can combine advantages both PtOx Pt, allowing better reverse blocking performance than plain metal diodes lower turn-on voltage oxidized ones. Moreover,...
Abstract We demonstrate vertical Pt/TiO 2 / β -Ga O 3 metal–dielectric–semiconductor (MDS) diodes and compare performance with co-fabricated Pt/ Schottky (SBDs). The MDS diode exhibits a lower turn-on voltage leakage current. In addition, the breakdown increased from 548 V for an SBD to 1380 diode. improvement in off-state characteristics compared while simultaneously reducing on-state losses leads power dissipation at all duty cycles, indicating great promise of this device architecture...
Single-event burnout (SEB) is experimentally observed in structurally improved vertical Beta-gallium oxide ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga2O3) Schottky barrier diodes (SBDs) with Pt/PtOx contacts and high-k field-plate (FP) dielectrics. These SBDs are resistant to alpha particle strikes up the in-air reverse bias voltage of 475 V, but SEB-induced...
Abstract We report the first demonstration of self-aligned gate (SAG) β -Ga 2 O 3 metal-oxide-semiconductor field-effect transistors (MOSFETs) as a path toward eliminating source access resistance for low-loss power applications. The SAG process is implemented with subtractively defined and etched refractory metal, such Tungsten, combined ion-implantation. experimental modeled DC performance representative device that achieved maximum transconductance 35 mS mm −1 an on-resistance ∼30 Ω 2.5 μ...
We report on vertical β-Ga2O3 power diodes with oxidized-metal Schottky contact (PtOx) and high permittivity (high-κ) dielectric (ZrO2) field plate to improve reverse blocking at both surfaces edges. The PtOx showed excellent forward transport near unity ideality factor similar minimum specific on-resistance as Pt. Moreover, the contacts facilitated higher breakdown voltage lower leakage current due their barrier height (SBH) by more than 0.5 eV compared that of Most importantly, reduced...
We demonstrated 500 °C operation of field-effect transistors made using ultra-wide bandgap semiconductor β-Ga2O3. Metal–semiconductor were fabricated epitaxial conductive films grown on an insulating β-Ga2O3 substrate, TiW refractory metal gates, and Si-implanted source/drain contacts. Devices characterized in DC mode at different temperatures up to vacuum. These variable-temperature measurements showed a reduction gate modulation the drain current due increase leakage across...
Ultra-wide bandgap (UWBG) materials have exciting potential for power electronics applications due to their high breakdown electric fields. However, current UWBG diodes that achieve fields tend higher turn-on voltage, counteracting the benefits conduction losses UWBGs are supposed offer. The added from increased voltage explored in this work, accounting as well hard and soft-switching with respect thermal limitations. It is shown of 2V or more prohibits achieving lower overall efficiency...
We report ultra-high permittivity of RF sputtered BaTiO3 films on AlGaN/GaN Metal–Insulator–Semiconductor High-Electron Mobility Transistors (MISHEMTs) via high temperature sputtering and subsequent annealing in nitrogen. developed a novel dielectric deposition methodology, which enables for field management while maintaining good off-state characteristics utilizing combination room elevated depositions BaTiO3. The layers are characterized with transmission electron microscopy to show...
β-Ga2O3 is of great interest for power electronic devices with efficiency beyond current generation Si, 4H-SiC, and GaN due to its large breakdown electric field ∼8 MV/cm. However, taking advantage this strength in diodes requires device engineering reduce leakage that arises at high fields. In work, we elucidate the transport mechanisms metal/TiO2/β-Ga2O3 diodes, showing thermionic emission an excellent descriptor forward reverse bias. It shown tunneling greatly suppressed, consequently,...
We demonstrate a passivated MESFET fabricated on (010) Si-doped <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> with breakdown over 2.4 kV without field plates, high Power Figure of Merit (PFOM), and estimated Huang's Material (HMFOM), owing to low gate...
This work demonstrates TiO2/β-Ga2O3 metal–dielectric–semiconductor (MDS) diodes with an average breakdown field beyond the material limits of SiC and GaN. These MDS have lower conduction losses higher voltage (Vbk) than cofabricated Schottky barrier (SBDs), simultaneously improving both on- off-state parameters that are typically in competition each other. With further optimized management using p-NiO guard rings (GRs), Ni/TiO2/β-Ga2O3 present a path to realistically utilize high critical...
<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta$</tex> -Ga <inf xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> is an ultrawide-bandgap material (4.6–4.9 eV) with a theoretical breakdown field of about 8 MV/cm [1]. Very few experimental results have been reported so far on the radiation response . In this work, ion-induced single-event burnout (SEB) experimentally observed in two...
Beta Gallium Oxide ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta$</tex> -Ga <inf xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> ) is an ultra-wide bandgap semiconductor (∼4.8 eV) with numerous merits positioning it to surpass the material limits other semiconductors for power electronic applications, namely a high predicted critical field strength of 8 MV/cm, controllable doping...
Beta-phase gallium oxide <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\beta-\mathrm{Ga}_{2}\mathrm{O}_{3})$</tex> has shown promise as a next-generation wide-bandgap semiconductor for use in power electronics. It possesses bandgap and expected critical field strength of ~4.8 eV ~8 MV/cm, respectively, surpassing the same measured characteristics GaN SiC [1]. Early work been successful demonstrating lateral metal-oxide-semiconductor...
Devices based on wide bandgap (WBG) semiconductors like silicon carbide (SiC), gallium nitride (GaN), and oxide (Ga 2 O 3 ) are ideal for high-power electronics in harsh environments. Among the WBG semiconductors, ultrawide (UWBG) β-phase ), E G ≈ 4.8 eV, is emerging as a replacement current commercially available power due to its generational improvements performance manufacturing cost [1]. Ga has high theoretical breakdown electrical field of 8 MV/cm which turn gives Baliga’s figure merit...
β-Ga2O3 epitaxy from metal-organic chemical vapor deposition (MOCVD) has exhibited low background defects and high mobility which are promising for high-power devices. Vertical field-plate Schottky diodes have been fabricated using MOCVD that showed punch through breakdown with a specific on-resistance (Ron,sp) of 0.67 mΩ-cm2. This Ron,sp is among the lowest comparable drift layer thickness reports can be contributed high-mobility epitaxy. We also demonstrated Pseudo vertical on thicker...