A5018794571- Ga2O3 and related materials
- ZnO doping and properties
- Semiconductor materials and devices
- GaN-based semiconductor devices and materials
- Electronic and Structural Properties of Oxides
- Silicon Carbide Semiconductor Technologies
- Advancements in Semiconductor Devices and Circuit Design
- Advanced Photocatalysis Techniques
- Ferroelectric and Negative Capacitance Devices
- Silicon Nanostructures and Photoluminescence
- Thin-Film Transistor Technologies
- Genomics and Phylogenetic Studies
- Nanowire Synthesis and Applications
- Identification and Quantification in Food
- Ferroelectric and Piezoelectric Materials
- Machine Learning in Bioinformatics
- Photonic Crystals and Applications
- Graphene research and applications
- MXene and MAX Phase Materials
- Acoustic Wave Resonator Technologies
- Semiconductor materials and interfaces
- Optical and Acousto-Optic Technologies
- Advanced Technologies in Various Fields
- Microwave Dielectric Ceramics Synthesis
- Refrigeration and Air Conditioning Technologies
Cornell University
2017-2024
University of California, Berkeley
2021-2024
University of California, Santa Barbara
2022
United States Air Force Research Laboratory
2021
The First People's Hospital of Shunde
2021
Southern Medical University
2021
Nanjing University
2004-2020
Philips (United States)
2020
Qorvo (United States)
2018
Collaborative Innovation Center of Advanced Microstructures
2004-2016
Gallium Oxide has undergone rapid technological maturation over the last decade, pushing it to forefront of ultra-wide band gap semiconductor technologies. Maximizing potential for a new system requires concerted effort by community address technical barriers which limit performance. Due favorable intrinsic material properties gallium oxide, namely, critical field strength, widely tunable conductivity, mobility, and melt-based bulk growth, major targeted application space is power...
High-voltage vertical Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> MISFETs are developed employing halide vapor phase epitaxial (HVPE) layers on bulk (001) substrates. The low charge concentration of ~10 <sup xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> cm xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> in the n-drift region allows three terminal breakdown voltages to...
We report the realization of field-plated vertical Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> trench Schottky barrier diodes (SBDs). The SBDs show significantly lower leakage current than regular SBDs. With employment field plate, a breakdown voltage (BV) 2.89 kV is achieved, which ~500 V higher those without plate. Trench sidewall depletion observed, and average width...
In this work, we demonstrate a novel conductivity-controlled junction termination extension (JTE) technique using p-type NiO—a key element for the potential commercialization of Ga2O3 power devices. The surface electric field at Schottky edge is effectively suppressed by NiO JTE. Simultaneously, it can control concentration to maximize breakdown voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math...
A high current density of 1 kA/cm2 is experimentally realized in enhancement-mode Ga2O3 vertical power metal-insulator field-effect transistors with fin-shaped channels. Comparative analysis shows that the more than doubled over prior art arises from a larger transistor channel width; on other hand, wider also leads to severe drain-induced barrier lowering therefore premature breakdown at zero gate-source bias. The observation higher confirms charge trapping gate dielectric limits effective...
β-Ga2O3 vertical trench Schottky barrier diodes (SBDs) are realized, demonstrating superior reverse blocking characteristics than the co-fabricated regular SBDs. Taking advantage of reduced surface field effect offered by metal-insulator-semiconductor structure, leakage current in SBDs is significantly suppressed. The devices have a higher breakdown voltage 1232 V without optimized management techniques, while having specific on-resistance (Ron,sp) 15 mΩ cm2. An ultra-low density &lt;1...
We investigate the intrinsic reverse leakage mechanisms in Ni-based Schottky barrier diodes (SBDs) fabricated on a (2¯01) single crystal β-Ga2O3 substrate, where uniform bulk current has been designed and confirmed. The temperature-dependent characteristics are analyzed by numerical model, which includes both image-force lowering doping effects. found that is near-ideal dominated tunneling throughout entire range of surface electric field from 0.8 MV/cm to 3.4 MV/cm. extracted height model...
This work demonstrates the high-frequency and high-power performance capacity of GaN high electron mobility transistors (HEMTs) on Si substrates. Using a T-gate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}^{++}$ </tex-math></inline-formula> -GaN source/drain contacts, InAlN/GaN HEMT with gate length 55 nm source-drain spacing 175 shows maximum drain current notation="LaTeX">${I}_{{D,MAX}}$ 2.8 A/mm...
We present the design principle and experimental demonstrations of GaN trench junction-barrier-Schottky-diodes(trench JBSDs), where Schottky contact within patterned trenches is at same plane as adjacent p-n junctions. Assisted by TCAD simulations, leakage current reduction mechanism identified reduced surface field (RESURF) effect due to barrier-height difference between junction junction. Design space for width stripe-shaped found be <;0.5 μm a drift layer doping level 10 <sup...
High-performance β-Ga203 vertical trench Schottky barrier diodes (SBDs) are demonstrated on bulk Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> substrates with a halide vapor phase epitaxial layer. A breakdown voltage (BV) of 2.44 kV, Baliga's figure-of-merit (BV <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /R xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> ) 0.39...
We demonstrate record-high performance in normally-off single and multi-fin b-Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> vertical power transistors. The effective channel mobility is significantly improved up to ~130 cm <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V·s with a post-deposition annealing process. With fin-channel width of 0.15 μm, true operation...
High-voltage vertical regrown p-n junction diodes on bulk GaN substrates are reported in this letter with molecular-beam-epitaxy p-GaN metalorganic-chemical-vapor-deposition grown n-GaN drift region. The highest breakdown voltage is measured at 1135 V, and the differential on-resistance 3.9 mOhm.cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> room temperature. forward I-V show a turn-ON near V an ideality factor of 2.5....
Ga2O3 vertical trench Schottky barrier diodes with four different fin-channel orientations are realized on (001) substrates and compared. Fin-channels along the [010] direction (100)-like sidewalls result in highest forward current, while other channel all lead to a shallow turn-on behavior much lower indicative of severe sidewall depletion attributed negative interface charges. The comparison indicates that charge density is smallest surfaces. breakdown voltage 1-μm fin width around 2.4 kV,...
Ultrawide bandgap (UWBG) semiconductors such as β-Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> can support a much higher electric field than traditional wide semiconductors, thus promising an unprecedentedly low conduction loss. However, the maximum in regular Schottky barrier diodes (SBDs) is limited due to constraint set by reverse leakage current. On other hand, trench SBD...
Here, we have explored the thermal stability of α-(Al,Ga)2O3 grown by molecular-beam epitaxy on m-plane sapphire under high-temperature annealing conditions for various Al compositions (i.e., 0%, 46%, and 100%). Though uncapped α-Ga2O3 undergoes a structural phase transition to thermodynamically stable β-phase at high temperatures, find that an aluminum oxide cap atomic layer deposition preserves α-phase. Unlike α-Ga2O3, 46% 100% content remain temperatures. We quantify evolution properties...
GaN vertical trench-MOSFETs incorporating molecular beam epitaxy (MBE) regrown channel are developed and investigated. The regrowth by MBE prevents repassivation of the p-type body while promising higher mobility. Two different designs lateral portion compared: without or with an n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -GaN buried layer. Without -buried layer, a respectable 600-V breakdown voltage (BV) is measured in absence...
Thermal activation of buried p-type GaN is investigated in metal-organic chemical vapor deposition-regrown vertical structures, where the p-GaN re-passivated by hydrogen during regrowth. The performed exposing through etched sidewalls and characterized reverse breakdown measurements on diodes. effect n-type doping level has been observed. After 725 °C/30 min annealing a dry air environment, with regrown unintentionally-doped (UID) capping layer sufficiently activated due to significant...
High performance Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> vertical FinFETs with a breakdown voltage of 1.6 kV, drain current density 600 A/cm <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> have been demonstrated in this work. Fin-shaped channels sub-micron widths lead to high threshold 4 V, and also provide strong RESURF effects reduce the leakage increase voltage. A...
The reverse leakage current through a Schottky barrier transitions from thermionic emission-dominated regime to tunneling-dominated as the surface electric field increases. In this study, we evaluate such transition (ET) in β-Ga2O3 using numerical model. ET is found depend on temperature but has an extremely weak dependence doping concentration and height; result, simple empirical expression can be derived capture near-universal of temperature. With help field-plate design, observed...
We present a detailed investigation of the trapping and detrapping mechanisms that take place in gate region β-Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> vertical finFETs describe related processes. This analysis is based on combined pulsed characterization, transient measurements, tests carried out under monochromatic light, with photon energies between 1.5 5 eV. The original...
We present a comprehensive study of the ON-resistance ( R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> ) Ga xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> trench-MOS Schottky barrier diodes (SBDs), with focus on effect sidewall interface trapping. Capacitance-voltage characteristics MOS-capacitors and current-voltage trench SBDs were all repeatedly measured under increasing...
Ultra-wide bandgap β-gallium oxide (Ga2O3) vertical device technologies are of significant interest in the context development next-generation kV-range power switching devices. In this work, thermal analysis fin channel-based metal–oxide–semiconductor field-effect transistors (or transistors—FinFETs) was performed using infrared microscopy and coupled electro-thermal modeling. FinFETs with different width channel spacing were characterized to study design trade-off when attempting minimize...
We present a unified thermionic emission (TE) and thermionic-field (TFE) model for the ideal reverse-bias leakage current in Schottky junctions. The TE–TFE analytical advances upon previous TFE models by Murphy–Good Padovani–Stratton, which are two most widely adopted community, major aspects: (i) applicability of expression therein is extended to near-zero surface electric fields an error-function correction, allowing calculation total nontrivial sum TE (over-the-barrier current)...