Patent ID: 7675060

Claim:
A semiconductor device comprising: an N-channel thin film transistor having a first gate electrode, a first gate insulating film formed over the first gate electrode, and a first crystalline semiconductor layer formed over the first gate insulating film, the first crystalline semiconductor layer including a first source region, a first drain region, and a first channel-forming region formed therebetween; and a P-channel thin film transistor having a second gate electrode, a second gate insulating film formed over the second gate electrode, and a second crystalline semiconductor layer formed over the second gate insulating film, the second crystalline semiconductor layer including a second source region, a second drain region, and a second channel-forming region formed therebetween, wherein a first mask is in contact with the first channel-forming region and a second mask is in contact with the second channel-forming region, wherein each of the first source and drain regions comprises phosphorus and a metal element and is in contact with the first gate insulating film, wherein each of the second source and drain regions comprises boron, phosphorus, and the metal element and is in contact with the second gate insulating film, wherein first source and drain electrodes are formed over and in contact with the first source and drain regions and the first mask, and second source and drain electrodes are formed over and in contact with the second source and drain regions and the second mask, and wherein each of the first crystalline semiconductor layer, the second crystalline semiconductor layer, the first mask, and the second mask is a single layer.