Enhanced Low-Damage Quantitative Hybrid Cyclic Etching for AlGaN/GaN Heteroepitaxy: Process Optimization and Device Performance Improvement
Open Access
- 17 November 2025
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Journal of the Electron Devices Society
- Vol. 13, 1158-1167
Abstract
The etching process is pivotal in the fabrication of GaN-based devices, directly influencing their performance. This study presents an enhanced low-damage hybrid cyclic etching technology for AlGaN/GaN heteroepitaxy structures, combining oxygen plasma oxidation with HCl etching to achieve atomic-scale precision. By carefully controlling the oxidation layer thickness, this method preserves a low surface roughness of 0.228 nm and achieves an etching rate of 0.45 nm/cycle with excellent consistency. Compared to conventional ICP dry etching and KOH wet etching evaluated under identical experimental conditions, the proposed technique significantly reduces etching-induced-damage. When applied to the ohmic contact formation of AlGaN/GaN HEMTs using the same metallization scheme and annealing process, devices fabricated with the new hybrid etching method demonstrated a significantly lower contact resistance of 0.76 Ω7mm compared to those using conventional ICP etching (1.21 Ω7mm) or no additional etching after SiN removal (1.37 Ω7mm). Furthermore, these devices exhibited a threshold voltage of -6.5 V, a saturation drain current density of 880.55 mA/mm, and a knee voltage of approximately 4 V. This method also demonstrates potential for recessed gate etching and post-dry-etching damage repair, offering a promising solution for low-roughness surfaces processing with broad application prospects.Keywords
Funding Information
- National Key Research and Development Plan of China (2021YFB3601100, 2023YFB2905200)
- National Natural Science Foundation of China (62471402)
- Key Research and Development Plan of Shaanxi Province, China (2023GXLH-084)
- Key Research and Development Project of Xi’an, China (23LLRH0048)
- Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University (CX2024086)
This publication has 20 references indexed in Scilit:
- Recent developments in materials, architectures and processing of AlGaN/GaN HEMTs for future RF and power electronic applications: A critical reviewMicro and Nanostructures, 2022
- A cost-effective technology to improve power performance of nanoribbons GaN HEMTsApplied Physics Letters, 2022
- Selectively dry etched of p-GaN/InAlN heterostructures using BCI3-based plasma for normally-off HEMT technologyMaterials Research Express, 2021
- GaN-based power devices: Physics, reliability, and perspectivesJournal of Applied Physics, 2021
- Effects of notch structures on DC and RF performances of AlGaN/GaN high electron mobility transistors*Chinese Physics B, 2020
- A Novel Oxygen-Based Digital Etching Technique for p-GaN/AlGaN Structures without Etch-Stop Layers*Chinese Physics Letters, 2020
- XPS study of a selective GaN etching process using self-limiting cyclic approach for power devices applicationMicroelectronic Engineering, 2020
- Defect-selective etching of GaN in a modified molten bases systemJournal of Crystal Growth, 2002
- Acid etching for accurate determination of dislocation density in GaNJournal of Electronic Materials, 2002
- Inductively coupled plasma etching of GaNApplied Physics Letters, 1996