Study Of Diluted Magnetic Semiconductor Mn-Doped GaN Growth By ECR-PEMOCVD

The materials of III-V Diluted Magnetic Semiconductors (DMS) doped transition metal Mn²+, Fe²+ etc, and ferromagnet/semiconductor heterostructures are expected to realize novel magnetic (or self-spin) electronic devices. These materials due to their combined properties of both magnetic materials and semiconductors will bring a technological revolution in conventional electronic industry. At the temperature far below room temperature, numerous DMS will lose its magnetism. But the DMS GaN Doped Mn (GaMnN) with a Curie Temperature higher than room temperature is one kind of the preferred materials which have carrier- induced ferromagnetism at room temperature or a higher temperature. The major works of this paper is the studies of initial film growth technology of self-organized (GaMn)N quantum dots at low temperature by using Electron-Cyclotron-Resonance Plasma Enhanced Metal Organic Chemical Vapor Deposition (ECR-PEMOCVD) on an ECR semiconductor processing device-upgrade(ESPD-U) developed in our lab. It includes the preprocessing of sapphire substrates (hydrogen plasma cleaning, nitrogen plasma nitrification and buffer layers growth), high quality GaN hetero-epitaxy on sapphire substrates at low temperature, and (GaMn)N epitaxy. In the experiments, TEGa and nitrogen plasma are used as sources of Ga and nitrogen respectively. Besides we discussed the effect on nitrogen plasma nitrification by different microwave power. Moreover, we find the "Temperature Windows" in the course of nitrification for different microwave power. The growth surfaces of fihns were monitoring in situ by reflective high-energy electron diffraction (RHEED) in the whole process. On the basis of the best cleaning conditions received in the past in laboratory, we have gotten the better nitrification parameters through changing nitrogen and hydrogen plasma, nitrification time and temperature, which is proved by the quality of GaN buffer. Through carefully analyzing the RHEED AFM(Atomic Force Microscope ) images and XRD(X-ray diffraction) Electronic Probes Raman Spectrum figures, we get the better process conditions and have successfully realized the nitrification of substrates and growth of GaN buffers, and then GaMnN DMS fihns exhibiting certain concentration of Mn and good crystal qualities were successfully grown on substrates sapphire (α-Al₂O₃) by using Mn source. The thesis study belong to the subject of National Nature Science Foundation (60476008) .