High-performance doped-channel field-effect transistor using graded SiGe channel

Experimental p-type Si/SiGe doped-channel field-effect transistors (DCFETs), utilizing a strained and graded Si1-xGex well as a conducting channel, have been Successfully fabricated. The graded variation of the Ge fraction in a channel-induced built-in field prevents transconductance from decreasing markedly under a forward gate bias and enhances carrier confinement in device operation. It is found that by grading the Ge fraction in the SiGe channel, DCFETs exhibit excellent properties of not only a higher current density but also an enhanced extrinsic transconductance and a linear operation over a wider dynamic range than devices with a uniform Ge profile at the same integrated Ge dose in a SiGe conducting well.