【作者】 梅俊平；

【导师】 刘彩池；

【作者基本信息】 河北工业大学 ， 材料物理与化学， 2011， 博士

【摘要】 GaN基体系材料具有禁带宽度宽、热稳定和化学稳定性好,波长范围大的特点,在光电子和微电子领域有着极其广泛的应用前景。本文利用MOCVD生长技术,在经过预处理的衬底上外延生长出高质量的GaN薄膜,并对GaN的特性进行了系统研究。另外,利用离子注入技术制备出过渡族金属掺杂的GaN基稀磁半导体,从注入引起的结构变化研究铁磁性的起源问题。结果如下:1.研究了蓝宝石衬底预处理的腐蚀工艺,结果表明:采用浓磷酸溶液,在265℃下,腐蚀45⁵0分钟,得到了具有较理想图形的蓝宝石衬底。2.利用XRD分析了衬底预处理对GaN薄膜晶体质量的影响。结果表明:在经过预处理的蓝宝石衬底上外延生长的GaN薄膜显出更好的结晶质量。其XRD（0002）面上的半峰宽为293arcsec,（10 2）面半峰宽为560arcsec;位错密度降低到9.6×10⁶cm^-2;在15μm×15μm尺寸内,其均方根粗糙度（RMS）为1.898nm;其压应力也降低到0.071GPa。3.研究了快速热处理对GaN薄膜性能的影响。随着退火温度的升高,GaN薄膜晶体质量逐渐提高。对GaN薄膜进行950℃快速热处理后,其（0002）面半峰宽为301arcsec;其载流子浓度则高达1×10¹⁸cm^-3。4.利用离子注入技术制备出过渡族金属（Fe、Ni）掺杂的GaN基稀磁半导体材料,观察到部分样品具有明显的室温铁磁性。注入热处理后GaN的晶体质量是由注入剂量和退火温度共同决定的。能量为150KeV,剂量为1×10¹⁶cm^-2的Fe离子注入,在800℃热退火处理后,GaN外延层的晶格质量较好且铁磁性最强。并在研究注入对微结构的影响的过程中,对铁磁性的起源进行了探讨。更多还原

【Abstract】 Gallium nitride materials have become one of the forefront research topics in semiconductor materials due to their excellent properties. In this paper, GaN films were grown on sapphire substrate by Metal Organic Chemical Vapor Deposition （MOCVD）. The properties of GaN were studied. In addition, Fe-, Ni-doped GaN thin films have been made by ion implantation technology and the origin of ferromagnetism was discussed. The main results are as followings:1. The etching technology of the sapphire substrate has been studied. The results showed that the sapphire substrates with ideal graphic were obtained in the H3PO4 etch solution at 265?C for 45⁵0min.2. The properties of the GaN epilayer were analyzed by X-ray diffraction （XRD）, Atomic force microscope （AFM） and Raman spectra in order to study the influence of the spphire substrate pretreated on the crystal quality of GaN film. These results showed that the GaN epilayer grown on the pretreated sapphire substrate exhibited excellent crystal quality, the XRD FWHMs of the GaN epilayer in （0002） plane and （10 2） plane were 293arcsec and 560arcsec, respectively; the dislocation density was reduced to 9.6×10⁶cm^-2; the residual stress was reduced to 0.071GPa.3. The effect of heat treatment on GaN epilayer was studied. The results showed that the quality of the GaN epilayer was improved by rapid thermal processor. The XRD FWHMs becomes narrow and the carrier concentration becomes larger. When the GaN epilayers were annealed at 950?C, the XRD FWHM of GaN （0002） plane is 301arcsec and the carrier concentration is up to 1×10¹⁸cm^-3.4. Fe^-, Ni-doped GaN films have been prepared by ion implantation and obviously room-temperature ferromagnetic behavior were obtained. The magnetic property of GaN samples was determined by the kind of ion, dose and annealing temperature. GaN epilayers with better lattice quality and ferromagnetic properties were obtained after being annealed at 800?C, when the dose of Fe ion with energy of 150keV was 1×10¹⁶cm^-2. In addition, the origin of ferromagnetism was discussed.更多还原