Microwave Resistivity of Thermally Oxidized High Resistivity Silicon Wafers

We used a microwave dielectric resonator to study how the process of thermal oxidation of high resistivity silicon wafers reduces the wafer microwave resistivity. Measurements were performed before surface thermal oxidation, after the oxidation, and after wet oxide removal. We show that the process of oxide growth decreases the microwave resistivity of the wafer from approximately 20 k Omega cm to as low as 400 Omega cm (typically to 1-2 k Omega cm), depending on the dielectric layer thickness and the growth process conditions. After the wet removal of SiO2, the resistivity of the wafers increased, but it did not reach the initial value.