Structural properties of InN films grown on sapphire substrates by microwave-excited metalorganic vapor-phase epitaxy

Abstract

The structural properties of InN films grown on (0001) sapphire (α-Al2O3) substrates are investigated by reflection high-energy electron-diffraction and x-ray-diffraction methods. The epitaxial relationship between the InN layer and the α-Al2O3 substrate is revealed to be (0001)InN //(0001)α-Al2O3 with [101̄0]InN//[101̄0] α-Al2O3, which is different from that of AlN and GaN epitaxial films. The x-ray rocking curve measurements prove that the crystalline quality of as-grown InN films is not so good, while it can be significantly improved by thermal annealing at temperatures of 450–500 °C within 10 min in nitrogen ambient. The improvement of quality is ascribed to the rearrangement of mosaic crystallites in the films through the movement of their boundaries during a short period of time.

Study of Epitaxial Relationship in InN Growth on Sapphire (0001) by RF-MBE

“…This does not agree with the previous reports [5][6][7] about the relationship between the main epitaxial relationship and the growth temperature. It is considered that this might be attributed to the difference of growth methods.…”

“…Yamaguchi et al [5] reported that InN films with the epitaxial relationship of [101 0] InN || [112 0] sapphire were obtained when they were grown at 450 C by metalorganic vapor phase epitaxy (MOVPE). On the other hand, Guo et al [6] reported that InN films, which were grown at 500 C by microwave-excited metalorganic vapor phase epitaxy (ME-MOVPE), were with [112 0] InN || [112 0] sapphire . In addition, Wakahara et al [7] Various parameters, such as growth method, growth process, substrate temperature and V/III ratio should be considered.…”

Heteroepitaxial growth of InN layers on (111) silicon substrates

“…Since the bulk substrate of this material is not available, films must be grown by heteroepitaxy on foreign substrates. Usually, sapphire is used as a substrate material for the heteroepitaxy because of its wide availability, hexagonal symmetry, and its ease in handling and pregrowth cleaning [1,4,5]. However, from the perspective of device technology, sapphire possesses severe problems as a substrate material because it is difficult to cleave.…”

Highly transparent conductive Ga doped ZnO films in the near-infrared wavelength range

“…All of the XRD h-2h scan profiles show the intense diffraction peaks appearing at about 34.0°, 72.0°and 41.7°corresponding to the ZnO (0002), (0004) of sapphire substrates diffraction peaks. In general, since most of heteroepitaxial films have a mosaic structure and variation of lattice spacing, the magnitude of the full wide half-maximum (FWHM) of diffraction peaks depends on the method of measurement [15]. The h-2h mode measurement cannot exactly detect the crystallinity of the ZnO thin films, because only variation of lattice spacing broadens the FWHM of this mode, Thus, the crystalline quality of ZnO films have been examined by XRCs using the double-crystal diffraction method.…”