Growth of polycrystalline indium aluminum nitride thin films on silicon (111) substrates

Abstract

Polycrystalline indium aluminum nitride (In, Al) N films were synthesized on silicon substrates using a stacked elemental layers (SEL) technique. Indium nitride and aluminum layers were deposited on Si (111) substrates through RF magnetron sputtering of indium target in Ar–N2 at 100°C and aluminum target in Ar atmosphere at 300 °C respectively. The deposited layers were annealed at 100 °C, 200 °C and 400 °C for four hours in a three zone ceramic furnace under nitrogen environment. The samples were characterized using an X-ray Diffractometer (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectrometer (EDX) and Atomic Force Microscope (AFM). XRD results indicated the formation of InN, AlInN and AlN phases which exhibited variations in the width and intensities with increase of the annealing temperature. Williamson–Hall (W–H) analysis of the diffraction peaks was carried out to estimate the structural parameters such as crystallite size, lattice strain, deformation stress and strain energy density. The FESEM results showed an increase in the grain size whereas the EDX analysis indicated a decrease in the aluminum contents with increase of the annealing temperature. The AFM measurements revealed a decrease in the surface roughness by increasing the annealing temperature from 100–200°C, however, the roughness was found to increase at 400°C.