Electrical Conductivity of Silicon Dioxide Thermally Grown on Silicon

Abstract

DC and ac electrical conductivities of silicon dioxide thermally grown on p‐ (boron‐doped) and n‐type (phosphorous‐doped) silicon have been measured in the temperature range of 25°–1100°C. Total dc conductivities varied from 10−9 to 10−16 Ω−1cm−1 in the temperature range of 25°–960°C. Arrhenius plots for total dc conductivities of grown on both the substrates exhibit two regions. Below 450°C, the conductivities were independent of temperature and are suggested to be governed by impurities. Above 450°C, the total dc conductivities increased with increase in temperature. The activation energies of conduction in the temperature range 500°–960°C were estimated to be 1.65 and 2.10 eV for grown on p‐ and n‐type silicon, respectively. DC polarization measurements carried out in this temperature range suggest that conduction in is ionic as well as electronic. The ionic conduction is believed predominantly to be due to the transport of oxygen ions. AC conductivities were also measured in the temperature range of 550°–1100°C. The activation energies for the conduction in this temperature range were estimated to be 1.55 eV for on p‐type silicon and 1.86 eV for on n‐type silicon. These values are in close agreement with the values reported in the literature. AC conductivity of grown on n‐type silicon was found to be lower than that of grown on p‐type silicon.