The Improvement of Output Characteristics in Tensile Strained-Si-on-Insulator NMOSFET by Channel Band Gap Adjustment

An asymmetric device, Si/tensile strained-Si heterojunction channel NMOSFET with a Si channel close to the source and a tensile strained-Si channel close to the drain, is fabricated by tilt angle Ge implantation on the source side of the tensile strained Si-on-insulator (SSOI) and followed by solid-phase recrystallization. This asymmetric device has different electron affinities and threshold voltages along the channel. It causes the redistribution of inversion carriers and lateral electric fields when the asymmetric device is turned on. Improved kink effect and channel length modulation are observed. In addition, the enhanced transconductance is also shown in the asymmetric device. This novel asymmetric device can improve the output characteristics of the NMOSFET fabricated by the SSOI substrate.