Metallic silicide forming method and method of manufacturing semiconductor device

A method of manufacturing a semiconductor device having a metallic silicide layer formed on a semiconductor region containing silicon, said method comprising the steps of:

• forming a first metal layer containing a first metal on said semiconductor region;
• forming a second metal layer containing a second metal on said semiconductor region so as to cover said first metal layer formed in said step of forming a first metal layer;
• and
• siliciding said semiconductor region with at least one of said first metal layer and said second metal layer by performing a heat treatment for said semiconductor region in which said second metal layer is formed so as to cover said first metal layer in said step of forming a second metal layer, forming said metallic silicide layer,
• wherein which said first metal layer is formed at such a first temperature that said semiconductor region is allowed to be silicided with said first metal in said step of forming a first metallic layer, and
• said second metal layer is formed at a second temperature lower than the first temperature in said step of forming a second metal layer.