Thermal management of ultra-thin SOI devices: effects of phonon confinement

We have considered effects of spatial confinement of acoustic phonons on silicon thermal conductivity and thermal management of ultra-thin silicon-on-insulator (SOI) structures. It has been shown that modification of the phonon modes in thin silicon layers (10 nm -100 nm) sandwiched between two layers of silicon dioxide leads to a significant increase of the phonon relaxation rates and corresponding drop of lateral lattice thermal conductivity. The latter may bring about additional degradation in the electrostatic discharge (ESD) failure voltage for ultra-thin SOI devices. Obtained results help to realize the importance of proper thermal management of ultra-thin SOI based devices. Our theoretical and numerical results are consistent with recent experimental measurements of lateral thermal conductivity.