Metal-organic molecular beam epitaxy growth of InN films on highly orientated TCO/Si(1 0 0) substrates

Abstract

This work reports on the heteroepitaxial growth of wurtzite indium nitride (InN) thin films on highly orientated n-ZnO buffer layer by RF metal-organic molecular beam epitaxy (RF-MOMBE) system. Highly orientated n-ZnO buffer layers were pre-sputtered using RF co-sputtering. We investigated the surface morphology and crystal structure properties by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), respectively. XRD pattern shows InN films were hexagonal wurtzite structure with preferential c-axis orientation. Electrical properties such as carrier concentration and mobility were performed by Hall measurement at room temperature. Particularly, the InN has high growth rate of 1.5 μm/h. SEM images also reveal the InN surface become rough as increasing the flow rate of trimethylindium (TMI) vapor. Meanwhile, the carrier mobility decrease at higher TMI flow rate. The phenomena probably originate from surface imperfection by excess In incorporation in the films. These results indicate that the high-quality buffer layer is essential for engineering the growth of InN on silicon wafer, and it might be also applicable for other lattice-mismatched III–V heteroepitaxial systems.