Profiling of inhomogeneous carrier transport properties with the influence of temperature in silicon-on-insulator films formed by oxygen implantation

Abstract

The nonhomogeneous distribution of the carrier transport properties in silicon on insulator thin films synthesized by oxygen implantation are determined using gate-controlled p-type Hall devices. The conductivity, Hall effect, and capacitance were measured between 77 and 300 K as a function of the gate voltage and then differentiated to obtain depth profiles. The hole mobility is high and nearly constant in the top 100 nm of the film but drops rapidly in the region containing implantation-induced defects. The very good quality of the top layer, similar to that of bulk Si, is confirmed by the temperature behavior of both the mobility and the ionized impurity concentration at various depths in the film. Acoustic phonon scattering is found to prevail above 120 K and Coulombian scattering below. A difference between the profile of the total number of holes and that of the mobile holes is observed at low temperatures and explained in terms of long-range potential fluctuations.