High Pressure Reactive Ion Etching of P-Doped Polysilicon with HCl

Abstract

Reactive ion etching of the P-doped polysilicon with high pressure HCl was extensively investigated in a single wafer etcher. Despite the high pressure, anisotropic etch was accomplished along with the high etch rate. Extremely high selectivity with respect to the gate oxide was achieved for the sample patterned without photoresist. Carbon-containing species produced by the reaction of the photoresist with the chlorinated plasma was identified and was suspected to be responsible for the enhanced oxide etch rate for samples with photoresist. An optical multichannel end point detector was also described.