Preparation Of Inn Epitaxy Films On Cu Substrates

Indium nitride (InN) , which exhibits high electron mobility and small direct band gap (0.7eV), is the potential material for the application on high-speed electronic devices and infrared optoelectronic devices. In this thesis, the growth of InN films on singlecrystal Cu substrates have been firstly studied by common Vacuum Evaporation Reaction method.In order to prepare the suitable metallic substrate for the growth of InN films, the growth of Cu films on Si(100) and Mica(001) have been investigated systematically first by Vacuum Evaporation Deposition method using the homemade evaporators. So far as Cu(100)/Si(100) concerned, the key point for successful growth of Cu(100) films on Si(100) is to keep the temperature of Si substrates close to room temperature in the initial stage. The perfect Cu(100) surface was achieved by a high deposition rate in the initial stage and a relative low deposition rate in the subsequent stage (the fast-slow deposition mode). However, the Cu(100) films was unstable when the temperature above 200℃due to the formation of Cu3Si. For Cu(111)/Mica(001) system, Cu(111) films can grow on mica substrates in the temperature range from 200℃to 400℃, and the surface roughness decreases with increasing the growth temperature. The Cu(111)/Mica(001) system is selected as the substrate for the epitaxial growth of InN films.InN films have been prepared by common Vacuum Evaporation Reaction method which use NH3 gas and evaporated In as N source and In source, respectively. A thin layer of epitaxial InN films can be grown on Cu(111) at the temperature of about 400℃with very low deposition rate of In. however, because of the low decomposition efficiency of NH3, the mean growth rate of the films is extremely low. The decomposition efficiency of NH3 can be improved obviously by using a homemade high temperature tungsten filament, and the InN epitaxial films was prepared successfully on the Cu(111) substrate under the condition of Ts=400℃, Iw=7.0A, PNH3=1.0×10-3Pa, and IIn=2.9A, indicating the feasibility of InN grown on Cu(111) by the Vacuum Evaporation Reaction method using a tungsten filament. According to the characterization of XRD and RHEED patterns, the structure of InN films grown on Cu(111) is the wurtzite structure, and a epitaxy relationship mode between InN and Cu(111) has also been proposed. Limited by the relative low decomposition efficiency of NH3, the growth rate of InN films is low. In order to elevate the growth rate of InN obviously, the decomposition efficiency of NH3 was required to be further induced.