Confinement Effect and Conduction Band Offset in DG-SOI MOSFETs: A Simulation Study

Abstract

Besides Quantum Confinement Effects (QCEs) seen in Ultra-Thin (UT) channel Double-Gate Silicon on Insulator (DG-SOI) MOS devices, the Band-offset variations between the oxide and the UT channel also impact device electrostatics, which is not adequately considered by the existing TCAD Models. Effective Mass Approximation (EMA) is one of the widely used approach which takes both QCEs and Conduction Band offset (CBO) variations into account. In this work, we ensure the accuracy of the EMA approach through benchmarking the results with the Tight-Binding Method (TBM), for an infinite potential well (equivalent to considering high CBO) case. Having corrected effective mass while also inserting suitable energy correction parameters, the accuracy of the EMA approach is now ensured. In this work, we show that by reducing the band-gap of the oxide material, the integrated charge density obtained using the Direct Tunneling (DT) model in TCAD can now accurately emulate the results obtained from the benchmarked Effective Mass Approximation (EMA) approach.