Surface Passivation Process for GaN-Based Electronic Devices Utilizing ECR-CVD SiNx Film

Tamotsu HASHIZUME  Ryuusuke NAKASAKI  Shin-ya OOTOMO  Susumu OYAMA  Hideki HASEGAWA  

IEICE TRANSACTIONS on Electronics   Vol.E84-C   No.10   pp.1455-1461
Publication Date: 2001/10/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Joint Special Issue on Heterostructure Microelectronics with TWHM 2000 (Topical Workshop on Heterostructure Microelectronics 2000))
Category: Novel Electron Devices
GaN,  passivation,  surface,  SiNx,  ECR,  

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Surface passivation process of GaN utilizing electron-cyclotron-resonance (ECR) excited plasma has been characterized and optimized for realization of stable operation in GaN-based high-power/high-frequancy electronic devices. From XPS analysis, the NH4OH treatment as well as the ECR-N2 and ECR-H2 plasma treatments were found to be effective in removing natural oxide and contaminants from the GaN surface. The SiNx/GaN structure prepared by the ECR excited plasma chemical vapor deposition (ECR-CVD) process showed better C-V behavior compared to the SiO2/GaN structure. Surface treatment process using the ECR plasma improved interface properties and achieved the Dit value of 21011 cm-2 eV-1 or less. An estimate of the valence band offset by XPS showed that the present SiNx/n-GaN structure has a type-I band lineup, suitable for the surface passivation of GaN-based devices. No pronounced stress remained at the SiNx/GaN interface, which was confirmed by Raman spectroscopy.