In situ Si doping of heteroepitaxially grown c-BN thin films at different temperatures

Abstract

Phase pure cubic boron nitride (c-BN) films have been epitaxially grown on (001) diamond substrates at 420 °C, 600 °C and 900 °C. Si was added during film growth at these different deposition temperatures in order to achieve in situ n-type doping. The Si concentration increases as the growth temperature decreases. The effects of the different deposition temperatures and the silicon concentration on the transport properties of the c-BN epitaxial films have been systematically investigated. The results demonstrate that the film doped at 420 °C has lower resistivity than the ones doped at elevated temperatures. The temperature dependence of the electron transport properties and their corresponding theoretical fittings reveal that the activation energy of Si doped films is about 0.3 eV and the increased Si concentration could improve the compensation from the deep-level acceptors.