A novel Si1-xGex/Si MOSFET

A novel Si_1-xGe_x channel Metal Oxide Semiconductor field effect transistor (MOSFET) is described. Si_1-x Ge_x alloy used was grown by means of molecular beam epitaxy (MBE). The band structure of the Si_1-xGe_x channel MOSFET is different from that of the silicon channel MOSFET. Because of this, the performance of the former is better than that of the latter. In the present study, 3-inch-diam, N-type, ⟨100⟩ oriented silicon wafers with resistivity of 2 ohm-cm were used. First, Si_1-xGe_x (x=0.1-0.7) layers were grown, with a thickness 0.5-0.8 nm. Then, a silicon buffer layer was grown. After that, a gate oxide layer 15 nm thick was grown at a temperature of 800°C. Following polysilicon growth, polysilicon was doped by implantation of phosphorus. The formations of source and drain were by also by implantation. The I-V curves of output with different dopant concentration were obtained. The main direct current parameters of measured Si_1-xGe_x/Si MOSFET are: the threshold voltage V_T=-1.3 V, the transconductance G_m=100-130 siemens, the breakdown voltage of source and drain is 13-16 V