On the feasibility of spherical harmonics expansions of the Boltzmann transport equation for three-dimensional device geometries

Accurate simulation of carrier transport requires the solution of Boltzmann´s transport equation (BTE), which can be obtained by higher-order spherical harmonics expansion (SHE) techniques. Unfortunately, the high computational effort of the SHE method has so far prevented its application to 3D geometries. We refine the SHE method by suggesting and evaluating numerical techniques which allow for efficient solution of higher-order expansions even in the unchartered 3D regime.