Thin films of rf-magnetron sputtered InN on mica: Crystallography, electrical transport, and morphology

Abstract

Reactive rf-magnetron sputtering has been employed for the growth of thin films of InN on the (001) face of mica at a variety of substrate temperatures from 50 to 550 °C. These films have been characterized by x-ray scattering, stylus profilometry, and electrical transport measurements, and their topography has been studied by SEM and STM. At low deposition temperatures, the InN films exhibit texture [(00.1)InN‖ (001)mica], while at higher deposition temperatures a large fraction of the grains are heteroepitaxial [(00.1)InN‖(001)mica, (2.0)InN · (060)mica]. The utility of the x-ray precession method in the determination of this heteroepitaxial relationship is highlighted. The films exhibit a local mobility maximum near a substrate temperature of 350 °C, beyond which a sharp increase in resistivity associated with voids and cracks owing to the onset of secondary grain growth leads to a dramatic decrease in electrical mobility. At the highest growth temperatures, however, the interconnection between grains improves and lower resistivity and higher mobility are re-established.