Sample: 2.2um AlGaN-GaN on 500um Si substrate.
Process steps done: In selected areas AlGaN-GaN is etched down to Si.
Target: Etch Si further down.

I don't use RIE for Si etch, because I suspect the physical bombardment of
plasma may
damage the top 17nm AlGaN.

Possible solution:  XeF2 isotropic Si etch because its only chemical process
without any RF

QUESTION: Does XeF2 attack AlGaN-GaN ?


Muhammad Qazi
Dept. of EE
University of South Carolina
Columbia, SC29208