The Preparation And Characteristics Of In_xGa_1-xN Films Deposited By ECR-PEMOCVD

InGaN ternary alloy is intensively studied and of great interest because its band gap energy can be continuously varied from the near infrared region of～0.7eV (InN) to the near UV region of～3.4eV (GaN). InGaN ternary alloy particular high quality In-rich InGaN alloys give potential applications in many crucial areas including whole solar spectrum, high efficiency, solar cells and high brightness light emitting diodes and so on.However, reports about the growth and study of InGaN ternary alloy were few, and it was hard to obtain high quality InGaN films. The reasons can be summarized as followed:1) the large difference in interatomic space between GaN and InN(10%) results in a solid phase miscibility gap;2) the discrepancy in the optimum growth temperature of GaN and InN is another reason;3) the big difference in the covalent radii of In and Ga tends to creat a large internal strain or causes phase separation thereby resulting in inhomogeneous properties in high In content InGaN ternary alloy.The experiments were carried out on the Electron Cyclotron Resonance-Plasma Enhanced Metal Organic Chemistry Vapor Deposition (ECR-PEMOCVD) equipment which is equipped Reflection High Energy Electron Diffraction (RHEED) to monitor in situ. InGaN films with different In-contents were grown from GaN templates on (0001) c-oriented sapphire substrates. Trimethylgallium (TMGa), Trimethylindium (TMIn), and high-purity N2were used for Ga, In, and N sources, respectively.InGaN films with different In-contents were grown from GaN templates on (0001) c-oriented sapphire substrates. Surface morphology was probed by atomic force microscopy (AFM). Structural properties were characterized by X-ray diffraction (XRD) using a D/Max-2400(Cu Kal:λ=0.154056nm). The thicknesses of the films were obtained by Zygo3D surface profiler. In-contents in InGaN epilayers were also checked by electron probe microanalysis (EPMA).The results of X-ray diffraction (XRD) in InGaN films confirm that they have excellent c-axis orientation. In-contents in InGaN epilayers are checked by electron probe microanalysis (EPMA), which reveals that In-fractions determined by XRD are in very good agreement with EPMA results, and the In-contents are0.06/0.1/0.33/0.58, respectively. Atomic force microscopy measurement reveals that the grown films have a surface roughness that varies between4.16and8.14nm. The results suggest that it is possible to deposit high-c-axis-orientation InGaN films with different In-content, especially high In-content.