Silicon Nitride Masking Integrity Characterization

Abstract

The masking integrity of a mask against an Sb diffusion is characterized as a function of ratio during the deposition and the oxygen partial pressure during the subsequent high‐temperature buried layer diffusion. Localized masking failure occurs with Si rich ratio during deposition equals 1.0. Sb penetration depth through the mask, measured by SIMS, increases by a factor of two‐three when the oxygen partial pressure during the buried layer diffusion is increased from 0.0145 to 0.0822 atmospheres. Total masking failure results with oxygen partial pressures greater than 0.100 atmospheres. The oxidation of is responsible for the oxygen partial pressure dependence of the Sb penetration depth.