A5063931499- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- Semiconductor materials and devices
- Radio Frequency Integrated Circuit Design
- Metallic Glasses and Amorphous Alloys
- Silicon Carbide Semiconductor Technologies
- ZnO doping and properties
- Semiconductor Quantum Structures and Devices
- Magnetic properties of thin films
- Advanced Power Amplifier Design
- Magnetic Properties and Synthesis of Ferrites
- Semiconductor materials and interfaces
- Advanced Fiber Laser Technologies
- Dielectric materials and actuators
- Extraction and Separation Processes
- Advanced Photocatalysis Techniques
- Electromagnetic wave absorption materials
- Anodic Oxide Films and Nanostructures
- Metal and Thin Film Mechanics
- Advanced Photonic Communication Systems
- Theoretical and Computational Physics
- Railway Engineering and Dynamics
- Magneto-Optical Properties and Applications
- Electronic and Structural Properties of Oxides
- Electronic Packaging and Soldering Technologies
University of California, Santa Barbara
2019-2024
Shanghai Electric (China)
2023
Tongji University
2019
Tsinghua University
2016-2019
Jiangxi Copper (China)
2011
Quanta Computer (China)
2003
Abstract Emerging for future spintronic/electronic applications, magnetic semiconductors have stimulated intense interest due to their promises new functionalities and device concepts. So far, the so-called diluted attract many attentions, yet it remains challenging increase Curie temperatures above room temperature, particularly those based on III–V semiconductors. In contrast concept of doping elements into conventional make semiconductors, here we propose oxidize originally ferromagnetic...
In this article, N-polar GaN-on-sapphire deep-recess metal–insulator–semiconductor (MIS)-high-electron-mobility transistors (HEMTs) with a breakthrough performance at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}$ </tex-math></inline-formula> -band are presented. Compared prior GaN MIS-HEMTs, thin cap layer and atomic deposition (ALD) ruthenium (Ru) gate metallization were used along high-quality...
This letter reports on the W-band power performance of N-polar GaN deep recess MIS-high electron mobility transistors (HEMTs) using a new atomic layer deposition (ALD) ruthenium (Ru) gate metallization process. The structure is utilized to control DC-RF dispersion and increase conductivity in access regions. ALD Ru effectively fills narrow T-gate stems aiding realization shorter lengths with lower resistance than prior work. In this work, length was scaled down 48 nm, resulting demonstration...
In this letter, the first four-finger (4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times25\,\,\mu \text{m}$ </tex-math></inline-formula> ) N-polar GaN high-electron-mobility transistor (HEMT) with an outstanding large signal performance of 712-mW (7.1 W/mm) 31.7% power-added efficiency (PAE) is demonstrated at 94 GHz. To best our knowledge, a record output power from single device cell in any...
In this letter, we report on Schottky barrier (SB) gate N-Polar GaN-on-sapphire deep recess high-electron-mobility transistors (HEMTs) with excellent dc, small signal and large performance. A device a length of 77 nm demonstrates very high extrinsic dc transconductance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$g_{m}$ </tex-math></inline-formula> ) 917 mS/mm at notation="LaTeX">$V_{\mathbf {D}}$ 3...
In this Letter, a series of metal-insulator-semiconductor capacitors consisting Si3N4 dielectrics with different thicknesses on GaN have been fabricated to investigate their interface states. The measurement value extracted from ultraviolet assisted capacitance-voltage methods can be explained by the existence spatially uniform hole traps in Si3N4. An improved model combining effects states and is proposed extract state density (Dit) accurately. Based model, Dit obtained extrapolating trap...
Combining excellent dispersion control with large breakdown voltage, deep recess N-polar GaN HEMT technology has demonstrated record high power densities [1] and efficiencies [2]–[3] from 2-finger devices <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$50-75\ \mu \mathrm{m}$</tex> gate peripheries at W-band. Employment of this in MMICs, however, will benefit larger periphery multi-finger to maximize the per unit cell thus reduce or even...
The electrical properties and trapping characteristics of Si3N4 SiO2 dielectrics grown in situ on (000-1) N-polar GaN by metal organic chemical vapor deposition are investigated this paper. fixed charges, densities near-interface trap states, interface density insulator semiconductor capacitors (MISCAPs) quantified using a capacitance-voltage measurement method which is assisted ultraviolet illumination applied voltage-stress. charges states located at or near the (SiO2)/N-polar as indicated...
In this work, we report on a GaN/AlGaN superlattice based normally-off hole channel FinFET devices. A combination of Schottky gate and 60 nm wide fins led to enhancement mode operation. The device had an on-current 13 mA/mm on-resistance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$300~\Omega $ </tex-math></inline-formula> .mm. simultaneously, large Ion/Ioff > 107 current modulation more than two orders...
The interface and bulk properties of aluminum-silicon-oxide (AlSiO) dielectric grown by metal-organic chemical vapor deposition (MOCVD) on (001) β-Ga2O3 were investigated systematically using a deep UV-assisted capacitance–voltage methodology. improved surface preparation with combination UV-ozone wet treatment reduced near-interface traps resulting in negligible hysteresis. An average state density 6.63 × 1011 cm−2 eV−1 AlSiO trap 4.65 1017 cm−3 quantified, which is half that for Al2O3...
N-polar GaN deep recess MISHEMTs devices have shown record mm-wave power density and efficiency under CW conditions, high linearity receive performance. Digital communication systems require from both transmitters receivers, low noise figure transmit efficiency. This manuscript shows several advances to enable this, including a very 20 dB OIP3/P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DC</inf> with 1.9 NF at 30 GHz, which uses peaked...
GaN W-band devices have shown remarkable power performances using passive load pull measurements. However, as the device peripheries increase to provide higher from a single cell, available matching range becomes greater limiting factor. Switching active pull, can cover entire Smith chart, given sufficient drive power. In this work, design of high-power on-wafer is shown, along with some configuration choices and associated tradeoffs in system performance flexibility. N-polar HEMT were...
The electrical properties and the interface abruptness of aluminum silicon oxide (AlSiO) dielectric grown in situ on 0001¯ N-polar (0001) Ga-polar GaN by metal organic chemical vapor deposition were studied means capacitance-voltage (CV) atom probe tomography (APT) measurements. growth AlSiO resulted a positive flatband voltage shift 2.27 V with respect to that GaN, which exemplifies influence surface polarization charge GaN-based semiconductor (MOS) devices. AlSiO/GaN(N-polar) was sharp,...
Abstract Recently, amorphous magnetic semiconductors as a new family of have been developed by oxidizing ferromagnetic metals/alloys. Intriguingly, tuning the relative atomic ratios Co and Fe in Co-Fe-Ta-B-O system leads to formation an intrinsic semiconductor. Starting from high Curie-temperature ferromagnets, these show Curie temperatures well above room temperature. Among them, one typical example is p-type 28.6 12.4 Ta 4.3 B 8.7 O 46 semiconductor, which has optical bandgap ~2.4 eV,...
The impact of post-metallization annealing N-polar AlSiO metal-oxide semiconductor (MOS) capacitors was investigated. Annealing in air at 320 °C and 370 reduced the density near-interface traps from 5.6 × 1011 to ~2.8 cm−2 extended region flat-band voltage stability low-leakage operation 0–2.6 0–4 MV cm−1 forward bias accumulation region. Moreover, fully suppressed instabilities within test range (−10 −25 V) depletion operation. robust dielectric results demonstrated this letter are...
In this letter, we report the Schottky barrier diode investigation of ruthenium (Ru) deposited by atomic layer deposition on N-polar GaN. The diodes showed near-ideal thermionic current behavior under forward bias and reverse at various temperatures. height values extracted from both regions agreed well each temperature was to be 0.77 eV room temperature. combination characteristic resulted in <; 2 μA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...
The flat-band voltage (VFB) stability and time-dependent-dielectric-breakdown of SiO2 Si3N4 films grown in situ on (000–1) N-polar GaN by metal organic chemical vapor deposition are investigated. VFB the SiO2-film was unstable only above a critical electric-field stress 4.3 MV cm−1, while at both low high electric fields. film exhibited time to failure 20 years occurring an field 4.9 cm−1 which 3 higher than that SiO2. This study contributes understanding dielectrics performance, devoted...
The bulk and interfacial properties of aluminum silicon oxide (AlSiO) on N-polar GaN were investigated systematically employing capacitance–voltage (C–V) methods metal–oxide–semiconductor capacitors using a thickness series the AlSiO dielectric. fixed charge density, electron slow trap fast density located near interface extracted to be –1.5 × 1012 cm−2, 3.7 1011 1.9 respectively. Using ultraviolet (UV) assisted C–V methods, an average state ∼4.4 cm−2 eV−1 hole concentration in ∼8.4 1018...
This work investigates the process of planar electrochemical etching pores in n-type nitrogen-polar GaN and effect pore morphology on regrown film surface quality. An increase anodization voltage was found to diameter reduce density with inclined sidewalls near porosified films. Simultaneously, a decrease hexagonal hillock size number following regrowth observed. It is proposed that vertical are essential demonstrate high quality coalescence. For smooth hillock-free 100 nm regrowth, an...
Coarser grains are more prone to serious electrode damage during their lithiation. In article number 1902150, Sa Li, Yunhui Huang, Ju Li and co-workers report that grain refinement by alloying can improve lithiation/delithiation ductility reduce Sn foil denser boundary sliding systems. A 50 µm self-standing Lix3Ag0.5Cu96.5Sn anode, prepared mechanical prelithiation, achieves good strength demonstrates a striking full-cell cycling performance.