Design, fabrication, and analysis of SiGeC heterojunction PMOSFETs

摘要

We present the evaluation of the strain-stabilizing capabilities of C in the Si/sub 1-x/Ge/sub x/ system. To demonstrate these effects, we have designed Si/sub 1-x-y/Ge/sub x/C/sub y/ heterojunction PMOSFET devices over a range of Ge concentrations, with thicknesses that would typically result in related or metastable films under normal processing conditions. The dc characteristics of Si/sub 1-x-y/Ge/sub x/C/sub y/, SiCe, and Si PMOSFETs (L=10 /spl mu/m) were evaluated at room temperature and at 77 K. In general, the saturation mobility in Si/sub 1-x-y/Ge/sub x/C/sub y/ devices is higher than that of Si/sub 1-x/Ge/sub x/ and Si devices at low gate bias and room temperature. This enhancement is attributed to the strain stabilization effect of C. With proper optimization of Ge and C concentrations, it is possible to fabricate devices with significant improvements in drive current under normal operating conditions (0-3 V, 300 K). This application of Si/sub 1-x-y/Ge/sub x/C/sub y/ in PMOSFETs demonstrates the potential benefits of using of C in the Column IV heterostructure system.