Patent ID: 8097527

Claim:
A method of forming an epitaxial layer on a silicon substrate, comprising: (a) providing a silicon substrate; (b) performing a wet-cleaning process onto the silicon substrate by using a fluoric acid (HF) solution diluted by distilled water; (c) performing a first plasma cleaning process onto the silicon substrate by providing a sulfur hexafluoride (SF 6 ) gas and one of the argon gas (Ar) and a hydrogen (H 2 ) gas, wherein fluorine (F) molecule or fluorine (F) compound generated in the wet-cleaning process are removed by the first plasma cleaning process; (d) after step (c), performing a second plasma cleaning process onto the wet-cleaned silicon substrate by providing a chlorine (Cl 2 ) gas and an argon (Ar) gas, wherein contaminants and impurities including sulfur (S) molecules and fluorine (F) molecules are generated in the first plasma cleaning process, and the contaminants and impurities are removed by the second plasma cleaning process; and (e) forming an epitaxial growth film on the silicon substrate after the step (d).