Electronic Transport in Laterally Asymmetric Channel MOSFET for RF Analog Applications

In this paper, an ensemble Monte Carlo investigation of the static and dynamic performances in the high-frequency domain of laterally asymmetric channel (LAC) bulk metal-oxide-semiconductor field-effect transistors (MOSFETs) is presented. A detailed comparison with a homogeneously doped bulk device is also included. The results presented show that the use of an asymmetric doping within the channel enhances nonequilibrium features as velocity overshoot, thus significantly improving the transconductance of the device. The gradual variation of doping is also responsible for a modification of the electrostatic conditions and the inversion charge profiles, provoking the reduction of the gate-to-source capacitance, a minor influence of surface scattering, reduced transit times, and higher mean free paths. A noticeable enhancement (as compared to a conventional device) in the RF and microwave frequency range of the dynamic performance of the transistors is also evidenced. This is mainly due to a better transconductance-to-current ratio, Early voltage, and open-loop gain, which are the results of the improvement of the charge transport conditions in the device at a microscopic level. Therefore, LAC MOSFETs can be a viable option to enhance the figures of merit of bulk silicon technology for high-frequency analog applications.