Abstract
This paper examines the impact of band structure on deeply scaled III–V devices by using a self-consistent 20-band sp3d5s∗-SO semiempirical atomistic tight-binding model. The density of states and the ballistic transport for both GaAs and InAs ultrathin-body n-MOSFETs are calculated and compared with the commonly used bulk effective mass approximation, including all the valleys (Γ, X, and L). Our results show that for III–V semiconductors under strong quantum confinement, the conduction band nonparabolicity affects the confinement effectivemasses and, therefore, changes the relative importance of different valleys. A parabolic effective mass model with bulk effective masses fails to capture these effects and leads to significant errors, and therefore, a rigorous treatment of the full band structure is required.
Keywords
Band structure, effective mass, injection velocity, MOSFETs, nonparabolicity, pseudopotential (PP), quantum confinement, tight-binding (TB), ultrathin-body (UTB)
Date of this Version
May 2008