scholarly journals Study on positive threshold voltage shift and DC characteristics of HEMTs using gate recess technique

2021 ◽  
pp. 2141013
Author(s):  
Hsin Che Lee ◽  
Cheng-Che Lee ◽  
Hsin Jung Lee ◽  
Wei Yu Lee ◽  
Wei Ching Chuang
Keyword(s):  
Buffer Layer ◽  
Threshold Voltage ◽  
Organic Chemical ◽  
Etching Time ◽  
High Electron ◽  
Threshold Voltage Shift ◽  
Positive Shift ◽  
Dc Characteristics ◽  
Aln Buffer ◽  
Gate Recess

In the present study, AlGaN/GaN high-electron-mobility transistors (HEMTs) were fabricated through metal–organic chemical vapor deposition. Gate recess etching, combined with inductively coupled plasma reactive ion etching, was adopted, and etching time was controlled to manipulate the threshold voltage [Formula: see text]. The DC characteristics of devices etched for 0–25 s were investigated. [Formula: see text] exhibited a 1.9-V positive shift in the device with the AlGaN layer etched for 25 s. The effect of an AlN buffer layer on the [Formula: see text] shift was also investigated. The [Formula: see text] of the HEMT etched for 25 s and without an AlN buffer layer exhibited a positive shift of 3.1 V.

DC Characteristics of Nanometer-Gatelength GaAS Mesfets

1991 ◽  
Vol 240 ◽  
Author(s):  
K. Nummila ◽  
M. Tong ◽  
A. A. Ketterson ◽  
I. Adesida
Keyword(s):  
Buffer Layer ◽  
Threshold Voltage ◽  
Epitaxial Layers ◽  
Short Channel ◽  
Threshold Voltage Shift ◽  
Subthreshold Current ◽  
Dc Characteristics ◽  
Channel Effects ◽  
Gaas Buffer Layer ◽  
Channel Thickness

ABSTRACTHigh-resolution electron-beam lithography has been used to fabricate GaAs MESFETs with gate-lengths ranging from 1 μm down to 30 nm. Devices were fabricated on two MESFET epitaxial layers; one with undoped GaAs-buffer layer while the other had a p- -GaAs-buffer layer. The DC characteristics including transconductance, output conductance, threshold voltage, and subthreshold current of these devices have been measured. Devices on both epitaxial layers exhibited significant short-channel effects. A negative threshold voltage shift and an increase in the subthreshold current were observed. These effects become prominent as the device aspect ratio (gate length/channel thickness) falls below 5. It is shown however that the effects were considerably suppressed in the layer with p- -GaAs buffer due to better confinement of electrons in the channel.

The Effect of AlN Buffer Layer on AlGaN/GaN/AlN Double‐Heterostructure High‐Electron‐Mobility Transistor

2019 ◽  
Vol 217 (7) ◽  
pp. 1900694
Author(s):  
Uiho Choi ◽  
Donghyeop Jung ◽  
Kyeongjae Lee ◽  
Taemyung Kwak ◽  
Taehoon Jang ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Electron Mobility ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
High Electron Mobility ◽  
Double Heterostructure ◽  
Aln Buffer

Effect of Temperature and Al Concentration on the Electrical Performance of GaN and Al0.2Ga0.8N Accumulation-Mode FET Devices

2010 ◽  
Vol 645-648 ◽  
pp. 1215-1218
Author(s):  
Marko J. Tadjer ◽  
Karl D. Hobart ◽  
Michael A. Mastro ◽  
Travis J. Anderson ◽  
Eugene A. Imhoff ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Drain Current ◽  
Electrical Performance ◽  
Effect Of Temperature ◽  
Organic Chemical ◽  
N Accumulation ◽  
Positive Threshold ◽  
Aln Buffer

Field-effect transistors were fabricated on GaN and Al0.2Ga0.8N epitaxial layers grown by metal organic chemical vapor deposition (MOCVD) on sapphire substrates. The threshold voltage VTH was higher when AlGaN was used as an active layer. VTH also increased with temperature due to the increased positive polarization charge at the GaN/AlN buffer/sapphire interfaces. Drain current increased at high temperatures even with more positive threshold voltage, which makes GaN-based FET devices attractive for high temperature operation.

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