Surface-roughness-scattering in non-planar channels — The role of band anisotropy

In this work, we investigate the effect of band structure anisotropy and channel orientation on SRS in non-planar channels such as tri-gate and GAA structures. A new formalism is introduced for calculating SRS rates for non-planar structures. The formalism is an extension of the theory by Prange and Nee for planar structures, which has been widely used for calculating the conductivity of inversion layers and thin films. We derive matrix elements for open and closed surfaces of arbitrary shape taking anisotropy of the band structure fully into account. Numerical experiments performed on tri-gate and GAA cross-sections indicate that SRS is greatly influenced by band anisotropy and channel orientation.