Selective area deposition of a-C:H films as masks for anisotropic etching of crystalline silicon in aqueous potassium hydroxide

Abstract

Amorphous hydrogenated carbon ( a-C:H) thin films deposited by r.f. chemical vapor deposition were investigated as a chemically resistant material for masking anisotropic etching of crystalline silicon by aqueous solution of KOH. Films with thicknesses varying from 50 to 80 nm were successfully patterned on silicon slices by the lift-off process. Then the samples were submitted to one aqueous etchant solution of KOH for 1h at a temperature of 78 °C. The inspection showed well defined etching pattern indicating the high chemical resistance of the a-C:H film to the aqueous KOH solution.