Patent Number: 8,716,145

Title: Critical concentration in etching doped poly silicon with HF/HNO.sub.3

Abstract: In some embodiments, the present invention discloses an etchant solution hydrochloric acid and nitric acid to etch doped polysilicon at low etch rates. The doped polysilicon can be doped with Ge, In, B and Ga. Preferably, the concentration of hydrochloric acid can be greater than 1 vol %, and the concentration of nitric acid is greater than 15 vol %.

Inventors: Huang; Shuogang (San Jose, CA)

Assignee: Intermolecular, Inc.

International Classification: H01L 21/302 (20060101); H01L 21/461 (20060101)

Expiration Date: 5/06/12018