Method for fabricating semiconductor device

A method for fabricating a semiconductor device, the method comprising steps of:

• providing a substrate having a nitride layer and a platinum (Pt)-containing nickel (Ni)-semiconductor compound layer, wherein the substrate has an active zone and a non-active zone, a first gate structure and a source/drain region disposed in the active zone, a second gate structure disposed in the non-active zone, and the step of providing the substrate having the nitride layer and the Pt-containing Ni semiconductor compound layer comprises:
• forming the nitride layer as being a second spacer on a sidewall of the second gate structure and as being a patterned hard mask to expose a source/drain region on the substrate;
• and
• forming the Pt-containing Ni semiconductor compound layer on the source/drain region;
• and
• in situ removing the nitride layer and platinum (Pt) atoms from the platinum (Pt)-containing nickel (Ni) semiconductor compound layer with a chemical solution including a sulfuric acid component and a phosphoric acid component.