Bandstructure effects in ultra-thin-body double-gate field effect transistor: A fullband analysis

Abstract

The properties of an n -channel ultra-thin-body (UTB) double-gate field effect transistor (DGFET), resulting from the bandstructure of the thin film Si channel, are discussed in this paper. The bandstructure has been calculated using a ten-orbital sp3d5 s+ tight-binding method. A number of intrinsic properties including band gap, density of states, intrinsic carrier concentration, and parabolic effective mass have been derived from the calculated bandstructure. The spatial distributions of intrinsic carrier concentration and 〈 100 〉 effective mass, resulting from the wave functions of different contributing subbands, are analyzed. A self-consistent solution of coupled Poisson-Schrödinger equations is obtained taking the full bandstructure into account, which is then applied to analyze volume inversion. The spatial distribution of carriers over the channel of a DGFET has been calculated and its effect on effective mass and channel capacitance is discussed. © 2008 American Institute of Physics.