Simulation and Performance Analysis of a Triple-material Gate GAA SNSTFT

Abstract

A Stacked Nano Sheet Gate All Around Thin Film Transistor (SNS GAATFT) with Triple Material (TM) has been proposed in this paper. The TM of the Thin Film Transistor (TFT) is varied by applying three different work functions (WFs) by having different gate materials being used. The transistor considered here for implementation is a p-channel device. The analysis has been carried out using the physical model: temperature-dependent carrier transport model (DD). Mobility Model (MM) includes the effects of doping concentration and electric field, Bandgap Narrowing Model (BNM) and Shockley-Read-Hall recombination Model (SRM) are for carrier lifetime. Synopsys Sentaurus TCAD has been used for the simulation of the proposed model and thus analyzing its characteristics. The characteristics of the proposed TM have been compared to those of the previously proposed Single Material (SM) SNS GAATFT model. For the proposed model, the first and third WFs were kept constant while the WF of the middle region varied between the first and third WFs. The output characteristics analyzed proved a better result for WF values closest to the third WF. Thus, a higher value of the middle WF was used in determining the different characteristics. From the characteristics it can be analyzed that due to varying electric potentials on the gate terminal due to varying WF, the influence of high-speed moving electron is reduced from the source side, and this helps in improving the carrier transport efficiency and thus, it is clear, this, in turn, helps in lowering the hot carrier effects. The comparison result shows that drain current in a TM is found to be almost 4 times higher than that of a SM model which shows better improvement in ION current.