Drain Current Model for Hetero-Dielectric Based TFET Architectures: Accumulation to Inversion Mode Analysis

Abstract

The paper presents an in-depth study of device physics and development of a generalized model (Accumulation-Depletion-Inversion Mode) for Hetero-Dielectric based TFET Architecture. A comparative study among single dielectric (high-k and low-k dielectric materials) and dual-dielectric (Hetero-Dielectric) based p-i-n and p-n-i-n TFET architectures has also been made. The model includes the impact of dielectric length variation and mobile charge carriers which has been validated through the Vgs and Vds dependent effective potential at the channel center of the device. Several physics based parameters such as surface potential, energy band profile, total electric field and drain current (both Ids-Vds and Ids-Vds) have also been investigated. Further, the model has been extended to optimize the Hetero-Dielectric p-n-i-n TFET by tuning the gate work function and length of the dielectric material. While optimization various static parameters such as Subthreshold Swing (SS), threshold voltage, Ion/Ioff ratio and dynamic performance parameters (parasitic capacitances) i.e. total gate capacitance (Cgg), gate to source capacitance (Cgs) and gate to drain capacitance (Cgd) have been investigated. The efficacy of the model has been validated through simulation results obtained using ATLAS device simulator.