Low-Pressure Chemical Vapor Deposition SiNx Process Study and Its Impact on Interface Characteristics of AlGaN/GaN MISHEMTs

Sun, Hu; Fan, Qian; Ni, Xianfeng; Luo, Qiang; Gu, Xing

doi:10.3390/mi16040442

Open AccessArticle

Low-Pressure Chemical Vapor Deposition SiN_x Process Study and Its Impact on Interface Characteristics of AlGaN/GaN MISHEMTs

by

Hu Sun

,

Qian Fan

,

Xianfeng Ni

,

Qiang Luo

and

Xing Gu

^*

Institute of Next Generation Semiconductor Materials, Southeast University, Suzhou 215123, China

^*

Author to whom correspondence should be addressed.

Micromachines 2025, 16(4), 442; https://doi.org/10.3390/mi16040442

Submission received: 24 March 2025 / Revised: 6 April 2025 / Accepted: 7 April 2025 / Published: 9 April 2025

(This article belongs to the Special Issue GaN-Based Materials and Devices: Research and Applications)

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Abstract

This study employed low-pressure chemical vapor deposition (LPCVD) SiN_x as both the gate dielectric layer and surface passivation layer, systematically investigating the effects of different growth conditions on the dielectric layer quality, two-dimensional electron gas (2DEG) characteristics, interface trap density, and devices’ performance, thereby optimizing the growth parameters of LPCVD SiN_x. The experiment investigated the effects of growth parameters such as the growth temperature, chamber pressure, and gas flow ratio on the growth rate of SiN_x during the process of growing SiN_x using the LPCVD technique. Further studies were performed to analyze the impact of SiN_x introduction on the 2DEG performance. The results indicated that both Si-rich and N-rich SiN_x compositions could enhance the 2DEG density improvement induced by SiN_x passivation. The impact of the gas flow ratio on the interface trap density is studied. Through the quantitative characterization of the interface trap density using the pulse-mode I_DS-V_GS method and frequency-dependent capacitance–voltage (C-V) measurement, the results show that the interface trap density decreases with an increased Si-to-N ratio.

Keywords: LPCVD SiN_x; 2DEG density; gas flow ratio; gate dielectric; interface trap density; passivation layer

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MDPI and ACS Style

Sun, H.; Fan, Q.; Ni, X.; Luo, Q.; Gu, X. Low-Pressure Chemical Vapor Deposition SiN_x Process Study and Its Impact on Interface Characteristics of AlGaN/GaN MISHEMTs. Micromachines 2025, 16, 442. https://doi.org/10.3390/mi16040442

AMA Style

Sun H, Fan Q, Ni X, Luo Q, Gu X. Low-Pressure Chemical Vapor Deposition SiN_x Process Study and Its Impact on Interface Characteristics of AlGaN/GaN MISHEMTs. Micromachines. 2025; 16(4):442. https://doi.org/10.3390/mi16040442

Chicago/Turabian Style

Sun, Hu, Qian Fan, Xianfeng Ni, Qiang Luo, and Xing Gu. 2025. "Low-Pressure Chemical Vapor Deposition SiN_x Process Study and Its Impact on Interface Characteristics of AlGaN/GaN MISHEMTs" Micromachines 16, no. 4: 442. https://doi.org/10.3390/mi16040442

APA Style

Sun, H., Fan, Q., Ni, X., Luo, Q., & Gu, X. (2025). Low-Pressure Chemical Vapor Deposition SiN_x Process Study and Its Impact on Interface Characteristics of AlGaN/GaN MISHEMTs. Micromachines, 16(4), 442. https://doi.org/10.3390/mi16040442

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Low-Pressure Chemical Vapor Deposition SiN_x Process Study and Its Impact on Interface Characteristics of AlGaN/GaN MISHEMTs

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