Electron Scattering by Mn Impurities in Si Detected by Cyclotron Resonance Measurement

Abstract

In this paper, we report on investigation of the low-temperature transport properties of silicon doped with transition metals, using the cyclotron resonance technique. For clarification of the states of metal impurities in silicon, secondary ion mass spectroscopy (SIMS), deep level transient spectroscopy (DLTS), and electron spin resonance (ESR), photoluminescence (PL) and Hall measurements were also performed. It was shown that of the various transition metals used, only manganese significantly affects the probability of electron scattering. The inverse relaxation time obtained from the cyclotron resonance linewidth varies with the square root of temperature. This temperature dependence cannot be explained by the typical scattering theories such as neutral shallow impurity scattering and ionized impurity scattering. We used high-resistivity silicon to display the contribution of transition metals effectively. Transition metals were doped by thermal diffusion at 1100°C after being evaporated onto the silicon surface. ESR measurements revealed the existence of interstitial manganese, while Hall measurements revealed a rather high density of Mn clusters. Following room temperature annealing, the intensity of the ESR signal for interstitial manganese rapidly decreased due to clustering, while the density of Mn clusters and the inverse relaxation time did not change significantly. Thus, the electron scattering was mainly caused by manganese clusters efficiently produced in the pure silicon host.