Thermal conduction in ultrathin pure and doped single-crystal silicon layers at high temperatures

Abstract

This work presents the in-plane thermal-conductivity data for pure as well as boron-doped ( 1.6 × 10 21 ∕ cm 3 ) , arsenic-doped ( 2.3 × 10 20 ∕ cm 3 ) , and phosphorus-doped ( 2.3 × 10 20 ∕ cm 3 ) silicon layers of thickness 30 nm in the temperature range of 300 – 450 K . The steady-state Joule heating and electrical resistance thermometry are used to measure the lateral thermal conductivity of suspended silicon layers. Thermal-conductivity data for pure and doped single-crystalline thin silicon layers can be interpreted using thermal-conductivity integral in relaxation-time approximation that accounts for phonon-boundary and phonon-impurity scatterings. No additional fitting parameters are used in this work in contrast with previous studies that required an unusually large phonon-impurity scattering coefficient to fit the thermal-conductivity data for bulk dopedsilicon to the predictions of the thermal-conductivity integral in relaxation-time approximation.