Patent ID: 7344999

Claim:
A cleaning method comprising: preparing a semiconductor substrate, wherein a silicon layer and a silicon germanium layer are formed on the semiconductor substrate, and the silicon layer and the silicon germanium layer are each exposed; performing a first cleaning sub-process, wherein the first cleaning sub-process comprises using a first cleaning solution to remove a native oxide layer from the semiconductor substrate; and, performing a second cleaning sub-process on the semiconductor substrate after performing the first cleaning sub-process, wherein the second cleaning sub-process comprises using a second cleaning solution, wherein the second cleaning solution comprises ammonium hydroxide (NH 4 OH), hydrogen peroxide (H 2 O 2 ), and deionized water (H 2 O), and the second cleaning solution comprises at least 200 times more deionized water (H 2 O) than ammonium hydroxide (NH 4 OH) by volume.