Abstract: A semiconductor device, includes a channel region, and a source/drain region adjacent to the channel region. The source/drain region includes a first epitaxial layer, a second epitaxial layer epitaxially formed on the first epitaxial layer and a third epitaxial layer epitaxially formed on the second epitaxial layer, and the first epitaxial layer is made of SiAs.

Abstract: A semiconductor device, includes a channel region, and a source/drain region adjacent to the channel region. The source/drain region includes a first epitaxial layer, a second epitaxial layer epitaxially formed on the first epitaxial layer and a third epitaxial layer epitaxially formed on the second epitaxial layer, and the first epitaxial layer is made of SiAs.

Abstract: A semiconductor device, includes a channel region, and a source/drain region adjacent to the channel region. The source/drain region includes a first epitaxial layer, a second epitaxial layer epitaxially formed on the first epitaxial layer and a third epitaxial layer epitaxially formed on the second epitaxial layer, and the first epitaxial layer is made of SiAs.

Abstract: A semiconductor device, includes a channel region, and a source/drain region adjacent to the channel region. The source/drain region includes a first epitaxial layer, a second epitaxial layer epitaxially formed on the first epitaxial layer and a third epitaxial layer epitaxially formed on the second epitaxial layer, and the first epitaxial layer is made of SiAs.

Abstract: A semiconductor device, includes a channel region, and a source/drain region adjacent to the channel region. The source/drain region includes a first epitaxial layer, a second epitaxial layer epitaxially formed on the first epitaxial layer and a third epitaxial layer epitaxially formed on the second epitaxial layer, and the first epitaxial layer is made of SiAs.

Abstract: A semiconductor device structure is provided. The semiconductor device structure includes a semiconductor substrate and a gate stack positioned over the semiconductor substrate. The semiconductor device structure includes spacers positioned over sidewalls of the gate stack. The semiconductor device structure includes a first protective layer positioned between the gate stack and the spacers and between the spacers and the semiconductor substrate. The semiconductor device structure includes a second protective layer positioned between the spacers and the first protective layer. The first protective layer and the second protective layer include different materials.

Abstract: A semiconductor device structure is provided. The semiconductor device structure includes a semiconductor substrate and a gate stack positioned over the semiconductor substrate. The semiconductor device structure includes spacers positioned over sidewalls of the gate stack. The semiconductor device structure includes a first protective layer positioned between the gate stack and the spacers and between the spacers and the semiconductor substrate. The semiconductor device structure includes a second protective layer positioned between the spacers and the first protective layer. The first protective layer and the second protective layer include different materials.