Silicon-On-Insulator Mosfets Fabricated in Zone-Melting-Recrystallized Poly-Si Films on SiO2

Abstract

ABSTRACTN- and p-channel enhancement-mode MOSFETs have been fabricated in Si films prepared by zone-melting recrystallization of poly-Si deposited on SiO2-coated Si substrates. The transistors exhibit high surface mobilities, in the range of 560–620 cm2/V−s for electrons and 200–240 cm2/V−s for holes, and low leakage currents of the order of 0.1 pA/μm (channel width). Uniform device performance with a yield exceeding 90% has been measured in tests of more than 100 devices. The interface between the Si film and the SiO2 layer on the substrate is characterized by an oxide charge density of 1–2 × 1011 cm−2 and a high surface carrier mobility. N-channel MOSFETs fabricated inSi films recrystallized on SiO2-coated fused quartz subtrates exhibit surface electron mobilities substantially higher than those of single-crystal Si devices because the films are under a large tensile stress.