Semiconductor device and manufacturing method thereof

A semiconductor device, comprising:

• a semiconductor substrate;
• a double diffused region in the semiconductor substrate;
• a gate structure overlapping at least a portion of the double diffused region;
• a drain region in the double diffused region and of a same conductivity type as the double diffused region;
• a first gate spacer alongside the gate structure and over the double diffused region;
• a drain silicide layer laterally extending from an outermost end surface of the first gate spacer along a top surface of the drain region;
• and
• a second gate spacer over the first gate spacer and having an outermost end substantially aligned with a boundary of the drain region, wherein the drain silicide layer is in contact with the first gate spacer and spaced apart from the second gate spacer.

A semiconductor device, comprising:

• a semiconductor substrate;
• a gate structure over the semiconductor substrate;
• a doped region in the semiconductor substrate and in the vicinity of a first side of the gate structure;
• a first source/drain region in the vicinity of a second side of the gate structure opposite the first side;
• a second source/drain region in the doped region and of a same conductivity type as the doped region;
• a multi-layer gate spacer laterally spacing the second source/drain region apart from the gate structure, the multi-layer gate spacer comprising a first spacer layer and a second spacer layer over the first spacer layer, and both the first and second spacer layers are in contact with a sidewall of the gate structure;
• and
• a gate silicide region on the gate structure and having a top surface higher than a topmost position of the multi-layer gate spacer.