Patent ID: 8470703

Claim:
A method of forming a semiconductor device, the method comprising: providing a substrate having an area including a source and a drain region of a transistor; forming a nickel (Ni) metal film on the substrate area including the source and the drain region; and performing a first heat-treatment process, including: heating the substrate including the metal film from a first temperature to a second temperature at a first ramping rate; and holding the substrate including the metal film at the second temperature for a first period of time; and then performing a second heat-treatment process, including: heating the substrate including the metal film from a third temperature to a fourth temperature at a second ramping rate; and holding the substrate at the fourth temperature for a second period of time, wherein the fourth temperature is different from the second temperature and the second period of time is different from the first period of time wherein the fourth temperature is higher than the second temperature; wherein the sequentially performed first and second heat-treatment processes convert the Ni metal layer on the source and drain regions into a NiSi layer on the source and drain regions and a NiSi 2 layer between the NiSi layer and the source and drain regions.