The effect of LAC doping on deep submicrometer transistor capacitances and its influence on device RF performance

In this paper, we have systematically investigated the effect of lateral asymmetric doping on the MOS transistor capacitances and compared their values with conventional (CON) MOSFETs. Our results show that, in lateral asymmetric channel (LAC) MOSFETs, there is nearly a 10% total gate capacitance reduction in the saturation region at the 100-nm technology node. We also show that this reduction in the gate capacitance contributes toward improvement in f_T, f_max, and RF current gain, along with an improved transconductance in these devices. Our results also show that reduced short-channel effects in LAC devices improve the RF power gain. Finally, we report that the lateral asymmetric channel doping gives rise to a lower drain voltage noise spectral density compared to CON devices, due to the more uniform electric field and electron velocity distributions in the channel.