scholarly journals Investigation of Recessed Gate AlGaN/GaN MIS-HEMTs with Double AlGaN Barrier Designs toward an Enhancement-Mode Characteristic

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 163 ◽  
Author(s):  
Tian-Li Wu ◽  
Shun-Wei Tang ◽  
Hong-Jia Jiang
Keyword(s):  
Gate Dielectric ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Al Content ◽  
Enhancement Mode ◽  
Electron Mobility Transistors ◽  
Algan Barrier ◽  
Mode Characteristic ◽  
Recessed Gate ◽  
Gate Region

In this work, recessed gate AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) with double AlGaN barrier designs are fabricated and investigated. Two different recessed depths are designed, leading to a 5 nm and a 3 nm remaining bottom AlGaN barrier under the gate region, and two different Al% (15% and 20%) in the bottom AlGaN barriers are designed. First of all, a double hump trans-conductance (gm)–gate voltage (VG) characteristic is observed in a recessed gate AlGaN/GaN MIS-HEMT with a 5 nm remaining bottom Al0.2Ga0.8N barrier under the gate region. Secondly, a physical model is proposed to explain this double channel characteristic by means of a formation of a top channel below the gate dielectric under a positive VG. Finally, the impacts of Al% content (15% and 20%) in the bottom AlGaN barrier and 5 nm/3 nm remaining bottom AlGaN barriers under the gate region are studied in detail, indicating that lowering Al% content in the bottom can increase the threshold voltage (VTH) toward an enhancement-mode characteristic.

Non-Recessed-Gate Enhancement-Mode AlGaN/GaN High Electron Mobility Transistors with High RF Performance

2004 ◽  
Vol 43 (4B) ◽  
pp. 2255-2258 ◽  
Author(s):  
Akira Endoh ◽  
Yoshimi Yamashita ◽  
Keiji Ikeda ◽  
Masataka Higashiwaki ◽  
Kohki Hikosaka ◽  
...  
Keyword(s):  
Electron Mobility ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
High Electron Mobility ◽  
Enhancement Mode ◽  
Electron Mobility Transistors ◽  
Rf Performance ◽  
Recessed Gate

scholarly journals Низкоэнергетическое бездефектное сухое травление барьерного слоя HEMT AlGaN/AlN/GaN

2018 ◽  
Vol 44 (10) ◽  
pp. 61
Author(s):  
С.В. Михайлович ◽  
А.Ю. Павлов ◽  
К.Н. Томош ◽  
Ю.В. Федоров
Keyword(s):  
Barrier Layer ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
High Electron Mobility ◽  
Inductively Coupled ◽  
Enhancement Mode ◽  
Electron Mobility Transistors ◽  
Algan Barrier ◽  
Algan Barrier Layer ◽  
First Time

AbstractA method of defectless dry etching of an AlGaN barrier layer is proposed, which consists in repeated plasmachemical oxidation of AlGaN and removal of the oxide layer by means of reactive ion etching in inductively coupled BCl_3 plasma. Using the proposed etching technology, AlGaN/AlN/GaN high-electron-mobility transistors (HEMTs) with a buried gate have been successfully fabricated for the first time. It is shown that the currents of obtained HEMTs are independent of the number of etching cycles, while the gate operating point shifts toward positive voltages up to obtaining transistors operating in the enhancement mode.

scholarly journals Gate Capacitance and Off-State Characteristics of E-Mode p-GaN Gate AlGaN/GaN High-Electron-Mobility Transistors After Gate Stress Bias

2021 ◽  
Author(s):  
Yu-Chen Lai ◽  
Yi-Nan Zhong ◽  
Ming-Yan Tsai ◽  
Yue-Ming Hsin
Keyword(s):  
Leakage Current ◽  
Electron Mobility ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
High Electron Mobility ◽  
Gate Capacitance ◽  
Enhancement Mode ◽  
Electron Mobility Transistors ◽  
Higher Power ◽  
State Capacitance

AbstractThis study investigated the gate capacitance and off-state characteristics of 650-V enhancement-mode p-GaN gate AlGaN/GaN high-electron-mobility transistors after various degrees of gate stress bias. A significant change was observed in the on-state capacitance when the gate stress bias was greater than 6 V. The corresponding threshold voltage exhibited a positive shift at low gate stress and a negative shift when the gate stress was greater than 6 V, which agreed with the shift observation from the I–V measurement. Moreover, the off-state leakage current increased significantly after the gate stress exceeded 6 V during the off-state characterization although the devices could be biased up to 1000 V without breakdown. The increase in the off-state leakage current would lead to higher power loss.

Improved device performance of recessed-gate AlGaN/GaN HEMTs using by in-situ N2O radical treatment

2022 ◽  
Author(s):  
Xinchuang Zhang ◽  
Mei Wu ◽  
Bin Hou ◽  
Xuerui Niu ◽  
Hao Lu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Electron Mobility Transistors ◽  
Device Performance ◽  
High Electron ◽  
Electron Mobility Transistors ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
Recessed Gate ◽  
Gate Recess

Abstract In this work, the N2O radicals in-situ treatment on gate region has been employed to improve device performance of recessed-gate AlGaN/GaN high-electron-mobility transistors (HEMTs). The samples after gate recess etching were treated by N2O radicals without physical bombardment. After in-situ treatment (IST) processing, the gate leakage currents decreased by more than one order of magnitude compared to the sample without IST. The fabricated HEMTs with the IST process show a low reverse gate current of 10-9 A/mm, high on/off current ratio of 108, and high fT×Lg of 13.44 GHz·μm. A transmission electron microscope (TEM) imaging illustrates an oxide layer with a thickness of 1.8 nm exists at the AlGaN surface. X-ray photoelectron spectroscopy (XPS) measurement shows that the content of the Al-O and Ga-O bonds elevated after IST, indicating that the Al-N and Ga-N bonds on the AlGaN surface were broken and meanwhile the Al-O and Ga-O bonds formed. The oxide formed by a chemical reaction between radicals and the surface of the AlGaN barrier layer is responsible for improved device characteristics.

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