PSG masks for diffusions in gallium arsenide

This paper describes the use of phosphosilicate glass (PSG) films as an effective mask against zinc and tin diffusions in gallium arsenide. It is shown that films with a high phosphorus pentoxide content (as much as 30 percent by weight) can be used to obtain adequate crack-free masks against these dopants. Effective masking was obtained for diffusion depths (unmasked regions) up to 10 µ.