Stress-enhanced carrier mobility in zone melting recrystallized polycrystalline Si films on SiO2-coated substrates

Abstract

Thermal stress is found to have a significant influence on the carrier mobilities in Si films prepared by zone melting recrystallization of polycrystalline Si on SiO2-coated substrates. Films recrystallized on SiO2-coated fused quartz substrates exhibit a large tensile stress, which enhances the electron mobility by ∼75% compared to the stress-free Si films recrystallized on SiO2-coated Si substrates. In contrast, Si films recrystallized on SiO2-coated sapphire substrates are under a large compressive stress, which yields an increase of ∼10% in hole mobility compared to the stress-free films.