Research

11 pages, 2566 KiB

Open AccessCommunication

Recess-Free E-Mode AlGaN/GaN MIS-HFET with Crystalline PEALD AlN Passivation Process

by Won-Ho Jang, Jun-Hyeok Yim, Hyungtak Kim and Ho-Young Cha

Electronics 2023, 12(7), 1667; https://doi.org/10.3390/electronics12071667 - 31 Mar 2023

Cited by 1 | Viewed by 1279

We utilized a plasma-enhanced atomic layer deposition (PEALD) process to deposit an AlN passivation layer on AlGaN/GaN surface to enhance the polarization effects, which enabled the fabrication of an enhancement-mode (E-mode) AlGaN/GaN metal-insulator-semiconductor heterojunction field-effect transistor (MIS-HFET) without the need for a gate [...] Read more.

We utilized a plasma-enhanced atomic layer deposition (PEALD) process to deposit an AlN passivation layer on AlGaN/GaN surface to enhance the polarization effects, which enabled the fabrication of an enhancement-mode (E-mode) AlGaN/GaN metal-insulator-semiconductor heterojunction field-effect transistor (MIS-HFET) without the need for a gate recess process. The AlN film deposited by PEALD exhibited a crystalline structure, not an amorphous one. The enhanced polarization effect of introducing the PEALD AlN film on a thin AlGaN barrier was confirmed through electrical analysis. To fabricate the E-mode AlGaN/GaN MIS-HFET, the PEALD AlN film was deposited on a 4.5 nm AlGaN barrier layer and then a damage-free wet etching process was used to open the gate region. The MIS-gate structure was formed by depositing a 15 nm plasma-enhanced chemical vapor deposition (PECVD) silicon dioxide (SiO₂) film. The fabricated thin-AlGaN/GaN MIS-HFET demonstrated successful E-mode operation, with a threshold voltage of 0.45 V, an on/off ratio of approximately 10⁹, a specific on-resistance of 7.1 mΩ·cm², and an off-state breakdown voltage exceeding 1100 V. Full article

(This article belongs to the Special Issue Nitride Semiconductor Devices and Applications)

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11 pages, 9929 KiB

Open AccessArticle

Influence of Proton Irradiation Energy on Gate–Channel Low-Field Electron Mobility in AlGaN/GaN HEMTs

by Qizheng Ji, Jun Liu, Ming Yang, Xiaofeng Hu, Guangfu Wang, Menglin Qiu and Shanghe Liu

Electronics 2023, 12(6), 1473; https://doi.org/10.3390/electronics12061473 - 20 Mar 2023

Cited by 1 | Viewed by 1286

Abstract

AlGaN/GaN high-electron-mobility transistors (HEMTs) with two different gate–drain distances (30

μ

m and 10

μ

m) were exposed to 1 MeV, 0.6 MeV, and 0.4 MeV protons at a fluence of 2.16 × 10¹² cm⁻². The gate–channel electron density and [...] Read more.

AlGaN/GaN high-electron-mobility transistors (HEMTs) with two different gate–drain distances (30

μ

m and 10

μ

m) were exposed to 1 MeV, 0.6 MeV, and 0.4 MeV protons at a fluence of 2.16 × 10¹² cm⁻². The gate–channel electron density and low-field mobility were obtained by measuring the capacitance–voltage characteristics and current–voltage characteristics. After proton irradiation, the gate–channel low-field electron mobility of the AlGaN/GaN HEMT with a 30

μ

m gate–drain distance increases and that with a 10

μ

m gate–drain distance decreases. It is studied and found that the mobility behavior is related to the polarization Coulomb field scattering, and the proton irradiation influences the intensity of the polarization Coulomb field scattering by changing the polarization/strain distribution in the barrier layer. The different gate–drain distances correspond to different variation trends of scattering intensity. The effect of 1 MeV protons on the barrier layer is smaller compared with 0.6 MeV and 0.4 MeV protons, so the mobility variation is smaller. Full article

(This article belongs to the Special Issue Nitride Semiconductor Devices and Applications)

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6 pages, 9641 KiB

Open AccessCommunication

p-GaN Selective Passivation via H Ion Implantation to Obtain a p-GaN Gate Normally off AlGaN/GaN HEMT

by Xiaoyu Ding, Xu Yuan, Tao Ju, Guohao Yu, Bingliang Zhang, Zhongkai Du, Zhongming Zeng, Baoshun Zhang and Xinping Zhang

Electronics 2023, 12(6), 1424; https://doi.org/10.3390/electronics12061424 - 16 Mar 2023

Cited by 1 | Viewed by 1776

Abstract

A dependable and robust technique for nanomachining is ion implantation. In this work, hydrogen (H) ion implantation was used, for the first time, to passivate p-GaN, except for the gate area, in order to create a normally off p-GaN/AlGaN/GaN high-electron-mobility transistor (HEMT). Ion [...] Read more.

A dependable and robust technique for nanomachining is ion implantation. In this work, hydrogen (H) ion implantation was used, for the first time, to passivate p-GaN, except for the gate area, in order to create a normally off p-GaN/AlGaN/GaN high-electron-mobility transistor (HEMT). Ion implantation passivation reduces H ion diffusion in p-GaN, allowing it to withstand temperatures above 350 °C. Through experiments and analyses, the H ion implantation energy and dosage required to passivate p-GaN, by generating Mg-H neutral complexes, were determined to be 20 keV and 1.5 × 10¹³ cm⁻², respectively. After conducting annealing procedures at various temperatures, we discovered that 400 °C was the ideal temperature to effectively obtain a normally off p-GaN HEMT. A threshold voltage of 0.8 V was achievable. The p-GaN HEMT also had a breakdown voltage of 642 V at a gate voltage of 0 V, maximum transconductance of 57.7 mS/mm, an on/off current ratio of 10⁸, an on-resistance of 8.4 mm, and a maximum drain current of 240.0 mA/mm at a gate voltage of 6 V after being annealed at 400 °C. Full article

(This article belongs to the Special Issue Nitride Semiconductor Devices and Applications)

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