Search query: high threshold voltage gan hemt

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abstract: In recent years, wide band gap semiconductor materials silicon carbide (SiC) and gallium nitride (GaN) are receiving widespread attention because of their superior performance. In particular, GaN devices have been applied in the fields of low voltage miniaturized power supplies and 5G communications. For GaN high electron mobility transistor (HEMT) devices used in miniaturized power supplies, the lower threshold voltage (Vth) is a problem that needs to be solved urgently. In this paper, the HEMT device having a novel mixed conducting channel. The device raises the threshold voltage to 3.21V while the saturation current capability still reached 0.46A/mm. As with conventional devices, the saturation current capability of the new device is affected by the Al composition of the barrier layer. But unlike conventional devices, the threshold voltage of the device can be adjusted by changing the doping concentration of the p type doped layer within a certain range.
author_names: Wanjie Li

Luqi Tao

Liming Wang

Xu Zhang

Xiandong Li

Xianping Chen
title: High threshold voltage GaN HEMT with mixed conductive channel
venue: 2020 21st International Conference on Electronic Packaging Technology (ICEPT)
year: 2020

abstract: Abstract The formation of partial AlGaN trench recess filled with multiple fluorinated gate dielectric layers as metal insulator semiconductor (MIS) gate structure for GaN based HEMT power devices is designed, fabricated and experimentally verified. The approach realizes the device normally off operational mode and at the same time is able to preserve the good mobility in the 2DEG channel for a maximum on state current. Experimental measurements on the fabricated MIS HEMT devices indicate a high gate threshold voltage V th at around 5 V and a very low gate leakage current at pA/mm level. This proposed gate structure provides very promising properties for GaN based power semiconductor devices in future power electronics switching applications.
author_names: Huolin Huang

Yung C Liang
title: Formation of combined partially recessed and multiple fluorinated dielectric layers gate structures for high threshold voltage GaN based HEMT power devices
year: 2015

abstract: Normally off p gallium nitride (GaN) gate high electron mobility transistors (HEMTs) on silicon substrate were fabricated with hydrogen plasma treatment technology, which features a high resistivity cap layer (HRCL) at the access region. With hydrogen plasma treatment at the access region, the normally off operation was obtained with a threshold voltage of +2.5 V based on the linear extrapolation of the transfer curve. The fabricated HRCL HEMT with a gate width of 49.7 mm exhibits a maximum drain current of 10 A at V GS 8 V and a high off state breakdown voltage of 567 V at V GS 0 V with substrate grounded. Meanwhile, the HRCL HEMT also shows low gate leakage current of 1.3 x 10 7 and 3.3 x 10 10 A/mm at V GS 8 V and 30 V, respectively. The positive threshold voltage, high drain current, high breakdown voltage and low gate leakage show the potential of HRCL HEMT for power switching applications.
author_names: Ronghui Hao

Dongdong Wu

Kai Fu

S H Liang

Chen Fu

Jie Zhao

Zhongkai Du

Bingliang Zhang

Qilong Wang

Guohao Yu

Kai Cheng

Yong Cai

Xinping Zhang

Baoshun Zhang
title: 10 A/567 V normally off p GaN gate HEMT with high threshold voltage and low gate leakage current
year: 2018

abstract: Temperature dependent threshold voltage (Vth) stability is a significant issue in the practical application of semi conductor power devices, especially when they are undergoing a repeated high temperature operation condition. The Vth analytical model and its stability are dependent on high temperature operations in wide bandgap gallium nitride (GaN) based high electron mobility transistor (HEMT) devices that were investigated in this work. The temperature effects on the physical parameters such as barrier height, conduction band, and polarization charge were analysed to understand the mechanism of Vth stability. The Vth analytical model under high temperature operation was then proposed and developed to study the measurement temperatures and repeated rounds dependent on Vth stability. The validity of the model was verified by comparing the theoretical calculation data with the experimental measurement and technology computer aided design (TCAD) simulation results. This work provides an effective theoretical reference on the Vth stability of power devices in practical, high temperature applications.
author_names: Huolin Huang

Feiyu Li

Zhonghao Sun

Yaqing Cao
title: Model Development for Threshold Voltage Stability Dependent on High Temperature Operations in Wide Bandgap GaN Based HEMT Power Devices
venue: Micromachines
year: 2018

abstract: We present an AlGaN/GaN high electron mobility transistor (HEMT) operating in enhancement mode (E mode) with metal insulator semiconductor (MIS) structure showing improved threshold voltage. The design includes an aluminium gallium nitride (Alo.3Gao.7N) barrier layer of 5 nm thickness and a silicon nitride (SiN) passivation layer. The passivation layer is used for controlling the charge density of electron gas in 2 dimension (2DEG) While aluminium oxide (Ah03) on AIGaN does not change the 2DEG charge density in the hetero interface, it increases the threshold voltage in enhancement mode. MIS HEMT operating in E mode shows a peak drain current density (IDS) of 975mA/mm and a threshold voltage (Vth) of 1.25 V. The drain current density can be increased with the increase of barrier layer charge concentration. On/off ratio and threshold voltage are compared with existing design available in literature. The significant improvement of device performance metrics can be done by controlling the charge concentration and the thickness of Alo.3Gao.7N barrier layer.
author_names: Mansura Sadek

Md Kawsar Alam
title: Threshold Voltage Improvement of Enhancement Mode Al2O3/ AIGaN/GaN MIS HEMT with High Drain Current Density
venue: 2018 10th International Conference on Electrical and Computer Engineering (ICECE)
year: 2018

author_names: Weijia Zhang
title: A Gate Sinking Threshold Voltage Adjustment Technique for High Voltage GaN HEMT
year: 2015

abstract: Fabrication of enhancement mode high electron mobility transistors (E HEMTs) on GaN/AlGaN heterostructures grown on SiC substrates is reported. Enhancement mode operation was achieved with high threshold voltage (V/sub T/ through the combination of low damage and controllable dry gate recessing and the annealing of the Ni/Au gates. As recessed E HEMTs with 1.0 /spl mu/m gates exhibited a threshold voltage (V/sub T/ of 0.35 V, maximum drain current (I/sub D,max/ of 505 mA/mm, and maximum transconductance (g/sub m,max/ of 345 mS/mm; the corresponding post gate anneal characteristics were 0.47 V, 455 mA/mm and 310 mS/mm, respectively. The RF performance is unaffected by the post gate anneal process with a unity current gain cutoff frequency (f/sub T/ of 10 GHz.
author_names: William B Lanford

T P Tanaka

Yohei Otoki

Ilesanmi Adesida
title: Recessed gate enhancement mode GaN HEMT with high threshold voltage
year: 2005

abstract: The shifts of electrical parameters for p GaN high electron mobility transistor (HEMT) under high off state bias stress with negative gate voltage are investigated in this paper. Comparing to the conventional off state bias stress with zero gate voltage, a more significant positive shift of threshold voltage and a more evident decrease of gate leakage current were observed under negative gate bias stress condition. The dominant degradation mechanism is suggested that electron traps induced by high electric field at gate source access region capture more electrons in the barrier layer with the increasing negative gate bias. This work is of significance for the researches on the long term reliability of the practical system using p GaN HEMT device.
author_names: Chi Zhang

Sihui Li

Siyang Liu

Jiaxing Wei

Wangran Wu

Weifeng Sun
title: Electrical Degradations of p GaN HEMT under High Off state Bias Stress with Negative Gate Voltage
venue: 2019 IEEE 26th International Symposium on Physical and Failure Analysis of Integrated Circuits (IPFA)
year: 2019

abstract: Abstract This article reports negative shift in the threshold voltage in AlGaN/GaN high electron mobility transistor (HEMT) with application of reverse gate bias stress. The device is biased in strong pinch off and low drain to source voltage condition for a fixed time duration (reverse gate bias stress) followed by measurement of transfer characteristics. Negative threshold voltage shift after application of reverse gate bias stress indicates the presence of more carriers in channel as compared to the unstressed condition. We propose the presence of AlGaN/GaN interface states to be the reason of negative threshold voltage shift, and developed a process to electrically characterize AlGaN/GaN interface states. We verified the results with Technology Computer Aided Design (TCAD) ATLAS simulation and got a good match with experimental measurements.
author_names: Amit Malik

Chandan Sharma

Robert Laishram

Rajesh K Bag

D S Rawal

Seema Vinayak

R K Sharma
title: Role of AlGaN/GaN interface traps on negative threshold voltage shift in AlGaN/GaN HEMT
year: 2018

author_names: Takaya Nagai
title: Diode Operation in Normally off GaN HEMT with High Controllability of Threshold Voltage
year: 2015