scholarly journals Improving Transport Properties of GaN-Based HEMT on Si (111) by Controlling SiH4 Flow Rate of the SiNx Nano-Mask

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 16
Author(s):  
Jin-Ji Dai ◽  
Cheng-Wei Liu ◽  
Ssu-Kuan Wu ◽  
Sa-Hoang Huynh ◽  
Jhen-Gang Jiang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Electron Mobility ◽  
Chemical Vapor ◽  
High Electron Mobility Transistor ◽  
Threading Dislocation ◽  
High Electron ◽  
Threading Dislocation Density ◽  
Dimensional Electron Gas ◽  
Short Time ◽  
The Impact

The AlGaN/AlN/GaN high electron mobility transistor structures were grown on a Si (111) substrate by metalorganic chemical vapor deposition in combination with the insertion of a SiNx nano-mask into the low-temperature GaN buffer layer. Herein, the impact of SiH4 flow rate on two-dimensional electron gas (2DEG) properties was comprehensively investigated, where an increase in SiH4 flow rate resulted in a decrease in edge-type threading dislocation density during coalescence process and an improvement of 2DEG electronic properties. The study also reveals that controlling the SiH4 flow rate of the SiNx nano-mask grown at low temperatures in a short time is an effective strategy to overcome the surface desorption issue that causes surface roughness degradation. The highest electron mobility of 1970 cm2/V·s and sheet carrier concentration of 6.42 × 1012 cm−2 can be achieved via an optimized SiH4 flow rate of 50 sccm.

The AlInGaN back barrier effect on DC characteristics of AlGaN/GaN high electron mobility transistor

2019 ◽  
Vol 33 (18) ◽  
pp. 1950190
Author(s):  
Hai Li Wang ◽  
Peng Yang ◽  
Kun Xu ◽  
Xiang Yang Duan ◽  
Shu Xiang Sun
Keyword(s):  
Mole Fraction ◽  
Electron Mobility ◽  
Transport Model ◽  
High Electron Mobility Transistors ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
High Electron Mobility ◽  
Conduction Band Offset ◽  
Electron Mobility Transistors ◽  
The Impact

In this paper, we investigated the impact of thickness and mole fraction AlInGaN back barrier on the DC performance of AlGaN/GaN high electron mobility transistors (HEMTs) by numerical simulation. The simulations are performed using the hydrodynamic transport model (HD). The simulation results indicated that an inserted AlInGaN back barrier with increasing thickness and mole fraction could effectively confine the electron in the channel, resulting in a significant improvement of the channel current and transconductance. Additionally, the variation of conduction band offset and the increase of total number electron in the channel led to the threshold voltage moving toward a more negative value.

scholarly journals Theoretical Study of InAlN/GaN High Electron Mobility Transistor (HEMT) with a Polarization-Graded AlGaN Back-Barrier Layer

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 885 ◽  
Author(s):  
Yan Gu ◽  
Dongmei Chang ◽  
Haiyan Sun ◽  
Jicong Zhao ◽  
Guofeng Yang ◽  
...  
Keyword(s):  
Electron Mobility ◽  
Theoretical Study ◽  
Lattice Relaxation ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Two Dimensional ◽  
Drift Diffusion ◽  
High Electron Mobility ◽  
Al Content ◽  
Dimensional Electron Gas

An inserted novel polarization-graded AlGaN back barrier structure is designed to enhance performances of In0.17Al0.83N/GaN high electron mobility transistor (HEMT), which is investigated by the two-dimensional drift-diffusion simulations. The results indicate that carrier confinement of the graded AlGaN back-barrier HEMT is significantly improved due to the conduction band discontinuity of about 0.46 eV at interface of GaN/AlGaN heterojunction. Meanwhile, the two-dimensional electron gas (2DEG) concentration of parasitic electron channel can be reduced by a gradient Al composition that leads to the complete lattice relaxation without piezoelectric polarization, which is compared with the conventional Al0.1Ga0.9N back-barrier HEMT. Furthermore, compared to the conventional back-barrier HEMT with a fixed Al-content, a higher transconductance, a higher current and a better radio-frequency performance can be created by a graded AlGaN back barrier.

Metal-Organic chemical vapor deposition of BN on sapphire and its heterostructures with 2D and 3D materials

MRS Advances ◽  
2016 ◽  
Vol 1 (32) ◽  
pp. 2273-2283
Author(s):  
Qing Paduano ◽  
Michael Snure
Keyword(s):  
Electron Mobility ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
High Electron Mobility Transistor ◽  
Layer Growth ◽  
Organic Chemical ◽  
Layer By Layer ◽  
High Electron ◽  
Two Dimensional ◽  
Direct Growth

ABSTRACTWe studied MOCVD processing for direct growth of BN on 2” sapphire substrates as a template for heterostructures with two dimensional (2D) and three dimensional (3D) materials. The combined experimental evidence points to three growth modes for BN: self-terminating, 3D random, and layer-by-layer, all of which are dependent on V/III ratio, temperature, pressure, and substrate surface modification via nitridation. At moderate temperature (950-1050°C), BN growth using high V/III ratio is self-terminating, resulting in c-oriented films aligned in-plane with respect to the orientation of the sapphire substrate. BN films grown under low V/III ratios are 3D, randomly oriented, and nano-crystalline. At higher temperature (1100°C), self-terminating growth transitions to a continuous layer-by-layer growth mode. When BN growth is self-terminating, films exhibit atomically smooth surface morphology and highly uniform thickness over a 2” sapphire wafer. Using these BN/sapphire templates we studied the growth of 2D and 2D/3D heterostructures. To study direct growth of 2D on 2D layered material we deposited graphene on BN in a continued process within the same MOCVD system. Furthermore, we explore the growth and nucleation of 3D materials (GaN and AlN) on BN. AlGaN/GaN based high electron mobility transistor (HEMT) structures grown on BN/sapphire exhibited two-dimensional electron gas characteristics at the AlGaN/GaN heterointerface, with room-temperature electron mobility and sheet electron density about 1900cm2/Vs and 1x1013cm-2, respectively.

A Charge Storage Based Enhancement Mode AlGaN/GaN High Electron Mobility Transistor

2018 ◽  
Vol 913 ◽  
pp. 870-875 ◽  
Author(s):  
Hui Wang ◽  
Ling Li Jiang ◽  
Ning Wang ◽  
Hong Yu Yu ◽  
Xin Peng Lin
Keyword(s):  
Electron Mobility ◽  
Gate Dielectric ◽  
High Electron Mobility Transistor ◽  
Charge Storage ◽  
High Electron ◽  
High Electron Mobility ◽  
Charge Trap ◽  
Enhancement Mode ◽  
A Charge ◽  
The Impact

In this work, a charge storage based enhancement mode (E-mode) AlGaN/GaN high electron mobility transistor (HEMT) is proposed and studied. A stacked gate dielectrics, consisting of a tunnel oxide, a charge trap layer and a blocking oxide are applied in the HEMT structure. The E-mode can be realized by negative charge storage within the charge trap layer during the programming process. The impact of the programming condition and the thickness of the dielectrics on the threshold voltage (Vth) are simulated systematically. It is found that the Vth increases with the increasing programming voltage and time due to the increase of the storage charge. Under proper programming condition, the Vth can be increased to more than 2 V. Moreover, It is also found that the Vth increases with the decrease of the thickness of the dielectrics. In addition, it is found that the breakdown voltage of such HEMT can be adjusted by varying the gate dielectric stacks.

Impact of AlN Spacer on Electron Mobility of AlGaN/AlN/GaN Structures on Silicon

2013 ◽  
Vol 740-742 ◽  
pp. 502-505 ◽  
Author(s):  
Sebastian Roensch ◽  
Victor Sizov ◽  
Takuma Yagi ◽  
Saad Murad ◽  
Lars Groh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Mobility ◽  
High Electron Mobility Transistor ◽  
Strong Impact ◽  
High Electron ◽  
High Electron Mobility ◽  
Alloy Scattering ◽  
The Impact ◽  
Scanning Electron

The impact of the thickness of an AlN spacer in AlGaN/AlN/GaN high electron mobility transistor (HEMT) structures on the Hall mobility was investigated in a range of 30 K - 340 K. The AlN spacer has a strong impact on the mobility at temperatures below 150 K. This effect is linked to a reduction of alloy scattering. Optical and scanning electron microscopy revealed hexagonal shaped defects which also have an effect on the mobility. These defects can be avoided by an appropriate adjustment of the AlN layer thickness.

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