MDPI - Publisher of Open Access Journals

12 pages, 11779 KB

Open AccessCommunication

Normally-Off Trench-Gated AlGaN/GaN Current Aperture Vertical Electron Transistor with Double Superjunction

by Jong-Uk Kim, Do-Yeon Park, Byeong-Jun Park and Sung-Ho Hahm

Technologies 2024, 12(12), 262; https://doi.org/10.3390/technologies12120262 - 16 Dec 2024

Viewed by 2435

This study proposes an AlGaN/GaN current aperture vertical electron transistor (CAVET) featuring a double superjunction (SJ) to enhance breakdown voltage (BV) and investigates its electrical characteristics via technology computer-aided design (TCAD) Silvaco Atlas simulation. An additional p-pillar was formed beneath the gate current blocking layer to create a lateral depletion region that provided a high off-state breakdown voltage. To address the tradeoff between the drain current and off-state breakdown voltage, the key design parameters were carefully optimized. The proposed device exhibited a higher off-state breakdown voltage (2933 V) than the device with a single SJ (2786 V), although the specific on-resistance of the proposed method (1.29 mΩ·cm⁻²) was slightly higher than that of the single SJ device (1.17 mΩ·cm⁻²). In addition, the reverse transfer capacitance was improved by 15.6% in the proposed device. Full article

(This article belongs to the Topic Advances in Microelectronics and Semiconductor Engineering)

► Show Figures

Figure 1

10 pages, 3112 KB

Open AccessArticle

High Current Density Trench CAVET on Bulk GaN Substrates with Low-Temperature GaN Suppressing Mg Diffusion

by Xinyi Wen, Kwang Jae Lee, Yusuke Nakazato, Jaeyi Chun and Srabanti Chowdhury

Crystals 2023, 13(4), 709; https://doi.org/10.3390/cryst13040709 - 21 Apr 2023

Cited by 6 | Viewed by 3898

Abstract

We report that, for the first time, a low-temperature GaN (LT-GaN) layer prepared by metal–organic chemical vapor deposition (MOCVD) regrowth was used as a Mg stopping layer (MSL) for a GaN trench current–aperture vertical electron transistor (CAVET) with p-GaN as a carrier blocking layer (CBL). Inserting LT-GaN on top of the p-GaN effectively suppresses Mg out-diffusion into the regrown AlGaN/GaN channel, contributing to the high current capability of GaN vertical devices with a p-GaN CBL. With different MOCVD growth conditions, MSLs inserted in trench CAVETs were comprehensively investigated for the influence of MSL regrowth temperature and thickness on device performance. With the best on-state current performance obtained in this study, the trench CAVET with a 100 nm thick MSL regrown at 750 °C shows a high drain current of 3.2 kA/cm² and a low on-state resistance of 1.2 mΩ∙cm². The secondary ion mass spectrometry (SIMS) depth profiles show that the trench CAVET with the 100 nm thick MSL regrown at 750 °C has a dramatically decreased Mg diffusion decay rate (~39 nm/decade) in AlGaN/GaN channel, compared to that of the CAVET without a MSL (~104 nm/decade). In developing GaN vertical devices embedded with a Mg-doped p-type layer, the LT-GaN as the MSL demonstrates a promising approach to effectively isolate Mg from the subsequently grown layers. Full article

(This article belongs to the Special Issue Research in GaN-based Materials and Devices)

► Show Figures

Figure 1

13 pages, 3789 KB

Open AccessArticle

Study of High-Performance GaN-Based Trench CAVET with Stepped Doping Microstructure

by Yuan Li, Liang Xu, Zhiyou Guo and Huiqing Sun

Micromachines 2022, 13(8), 1273; https://doi.org/10.3390/mi13081273 - 7 Aug 2022

Cited by 3 | Viewed by 2881

Abstract

In this article, an innovative GaN-based trench current-aperture vertical electron transistor (CAVET) with a stepped doping microstructure is proposed and studied using Silvaco-ATLAS. According to the simulation and analyzed characteristics, the best performance renders a remarkable Baliga’s figure of merit (FOM) of 4.767 GW·cm² owing to the modulation of the electric-field distribution. By adjusting the size of the stepped doping microstructure and doping concentration in the GaN drift, the maximum optimized result can achieve a relatively high breakdown voltage (BV) of 2523 V with a very low specific on-resistance (R_on,sp) of 1.34 mΩ·cm², or the BV can be improved to 3024 V with a specific on-resistance (R_on,sp) of 2.08 mΩ·cm². Compared with the conventional superjunction GaN-based trench CAVET, the newly demonstrated structure can achieve a 43% reduction in R_on,sp and increase by almost 20% the original BV. These results indicate the superiority of using the stepped doping microstructure in a trench CAVET to improve the BV and decrease R_on,sp, providing a reference for further development of GaN-based CAVETs. Full article

(This article belongs to the Special Issue III–V Compound Semiconductors and Devices)

► Show Figures

Figure 1

9 pages, 2495 KB

Open AccessArticle

Comparison of MOCVD and MBE Regrowth for CAVET Fabrication

by Simon Kotzea, Wiebke Witte, Birte-Julia Godejohann, Mathias Marx, Michael Heuken, Holger Kalisch, Rolf Aidam and Andrei Vescan

Electronics 2019, 8(4), 377; https://doi.org/10.3390/electronics8040377 - 28 Mar 2019

Cited by 12 | Viewed by 6712

Abstract

In this paper, we demonstrate the fabrication of current aperture vertical electron transistors (CAVET) realized with two different epitaxial growth methods. Templates with a p-GaN current blocking layer (CBL) were deposited by metal organic chemical vapor deposition (MOCVD). Channel and barrier layers were then regrown by either molecular beam epitaxy (MBE) or MOCVD. Scanning electron microscope (SEM) images and atomic force microscope (AFM) height profiles are used to identify the different regrowth mechanisms. We show that an AlN interlayer below the channel layer was able to reduce Mg diffusion during the high temperature MOCVD regrowth process. For the low-temperature MBE regrowth, Mg diffusion was successfully suppressed. CAVET were realized on the various samples. The devices suffer from high leakage currents, thus further regrowth optimization is needed. Full article

(This article belongs to the Section Semiconductor Devices)

► Show Figures

Figure 1

Search Results (4)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (4)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI