Improving the Electrical Performance of a Quantum Well FET With a Shell Doping Profile by Heterojunction Optimization

Abstract

This paper investigates the impacts of typical semiconductor material properties-electron affinity, bandgap, and dielectric constant, on the electrical performance of a p-type core-shell heterojunction nanowire FET by numerical simulations. At the heterojunction, a valence band offset of 200 meV forms a sufficient energy barrier confining the holes in the quantum well, resulting in the optimal OFF-state current. A higher dielectric constant of the shell region is found to be able to decrease the leakage current of the device. The optimum conditions from the parameter analysis are demonstrated by a realistic and achievable material combination of Si/SiGe for the core-shell configuration. This paper provides physical insights into the materialwise impacts for designing the proposed transistor showing the reduced OFF-current and a better subthreshold swing for low-power applications.