Impact of high-k gate dielectric on analog and RF performance of nanoscale DG-MOSFET

Abstract

Now a days, high-k dielectrics have been investigated as an alternative to Silicon dioxide (SiO2) based gate dielectric for nanoscale semiconductor devices. This paper is an attempt to characterize the analog and RF performance of the high-k metal gate (HKMG) double gate (DG) metal oxide semiconductor field effect transistor (MOSFET) in nanoscale through 2-D device simulation. The results demonstrates the impact of high-k oxide layer as single and gate stack (GS). The key idea behind this investigation is to provide a physical explanation for the improved analog and RF performance exhibited by the device. The major figures of merit (FOMs) studied in this paper are transconductance (gm), output conductance (gd), transconductance generation factor (gm/ID), early voltage (VEA), intrinsic gain (AV), cut off frequency (fT), transconductance frequency product (TFP), gain frequency product (GFP) and gain transconductance frequency product (GTFP). The effects of downscaling of channel length (L) on analog performance of the proposed devices have also been presented. It has been observed that the performance enhancement of GS configurations (k=7.5 i.e device D5 in the study) is encouraging as far as the nanoscale DG-MOSFET is concerned. Also it significantly reduces the short channel effects (SCEs). Parameters like DC gain of (91.257dB, 43.436dB), nearly ideal values (39.765V−1, 39.589V−1) of TGF, an early voltage of (2.73V, 16.897V), cutoff frequency (294GHz, 515.5GHz) and GTFP of (5.14×105GHz/V, 1.72×105GHz/V) for two different values of VDS=0.1V and 0.5V respectively are found to be close to ideal values. Analysis shows an opportunity for realizing high performance analog and RF circuits with the device proposed in this paper i.e. device D5.