| As MOSFETs are scaled, the devices show cut-off frequencies in the RF range. Their output resistance is degraded by short channel effects (SCEs), such as drain induced barrier lowering (DIBL), channel length modulation (CLM) and the Kink effect. These SCEs degrade the intrinsic gain (gm*Rout) and limit the application of MOSFETs in mixed-mode (digital and analog) devices. By increasing channel doping, SCEs can be suppressed, but high channel doping also results in low carrier mobility. There is a trade-off between transconductance and output resistance. To improve the intrinsic gain, increasing both transconductance and output resistance are important. Therefore, a novel heterojunction channel device is proposed to improve the output characteristics.;This heterojunction channel device is laterally composed with different electron affinities and threshold voltages along the channel. The heterojunction structure with different threshold voltages along the channel will cause the redistribution of inversion carriers and electric fields, which are enhanced electric fields close to the source side and reduced electric fields close to the drain side. In addition, the large threshold voltage close to the source side can screen the drain side electric field and suppress DIBL. Therefore, this device is expected to have enhanced transconductance and improved output resistance. A Si/Strained-Si heterojunction channel fabricated by solid phase recrystallization (SPR) method is proposed and experimentally evaluated.;In low power applications, active power (CVDD2f) and standby power (IOFFVDD) need to be reduced. Reducing VDD and IOFF can decrease power consumption. To resolve these challenges, novel devices with ultra-high ION/IOFF (and high ION) under a reduced-supply voltage are required. A device with a steep subthreshold swing (<60 mV/dec) is necessary. Currently, the novel carrier injection mechanisms, tunnel FETs (TFETs), are considered candidates for low power devices. However, the steep subthreshold swing in a low current level and the low turn-on current limit their application in low power devices. To improve the device performance, a TFET with a fully depleted source pocket fabricated using laser annealing is proposed to obtain a steep subthreshold swing (<60 mV/dec) and a large turn-on current. |
