Minority carrier mobility of Czochralski-grown silicon by microwave-detected photoconductance decay

Abstract

In this article the contactless microwave detected photoconductance decay technique (MW-PCD) is used to examine two important issues relating to carrier mobility. One is whether or not minority and majority carrier lattice scattering mobilities are equal, and the other whether or not mobilities depend on growth method of the semiconductor material. To answer these two questions, the minority carrier mobility for Czochralski-grown silicon has been measured by the MW-PCD method. The results are compared with both majority carrier mobility measurements for this material and minority carrier mobility values for float-zone material. The method employed by the MW-PCD analysis also yields bulk lifetime estimates. The results confirm earlier suspicions that differences in material quality can be the reason for differences between minority and majority carrier mobility measurements at doping levels below 1017 cm−3 rather than any fundamental difference in the scattering mechanisms of the two types of carriers.