Authors: S. Krishnan, D. Vasileska and M.V. Fischetti
Affilation: Arizona State University, United States
Pages: 72 - 75
Keywords: strained SiGe, Valence band-structure, 6 band k.p
We use a Monte Carlo method to investigate hole transport in ultrasmall p-channel MOSFETs with gate lengths of 25 nm. To model band-structure effects like warping, anisotropy and non-parabolicity on carrier transport, our device simulator couples a 2D Poisson solver with a discretized 6_6 k.p Hamiltonian solver  that includes the effect of the confining potential and provides the subband structure in the channel region. To reduce the computational cost, carriers in the source and drain regions are treated as quasi 3D particles unlike previous approaches [2, 3], where they were treated quantum mechanically using appropriate boundary conditions. The band-structure information for carriers in the source/drain regions is included by solving for the eigenenergies of a more compact 6_6 k.p Hamiltonian. Surface channel strained-Si p-MOSFETs and buried channel strained-SiGe MOSFETs can be simulated by including the 6_6 strain Hamiltonian into the problem. By comparing a previous effective mass approach using a simple parabolic two band model  with the current full-band model, we find that the effective mass model underestimates phonon-limited current by about 14%.