在Si(111)衬底上,以MOCVD方法高温外延生长的AlN为缓冲层,使用氢化物气相外延(HVPE)方法外延生长了15μm的c面GaN厚膜。并利用X射线衍射(XRD)、光致发光谱(PL)、拉曼光谱(Raman)等技术研究了GaN厚膜的结构和光学性质。分析结果表明,GaN厚膜具有六方纤锌矿结构,外延层中存在的张应力较小,为0.17GPa,在363.7nm处具有很强的GaN带边发光峰,没有黄带出现。AlN缓冲层有效地阻止了Si衬底和反应气体发生非生长的附加反应,并减小了GaN厚膜自身残余应力,有利于Si(111)衬底上HVPE GaN厚膜的生长。
C-plane GaN thick films have been successfully grown on Si(111) substrates with AlN as buffer layers by hydride vapour phase epitaxy(HVPE) system.Raman scattering,X-ray diffraction(XRD),and photoluminescence(PL) measurements are used to analyze the structure and properties of the GaN films.The results indicated that the structure of the film is hexagonal wurtzite,the biaxial stress of film is tensile and the value is 0.17GPa,the band edge emission of the GaN thick film is at 363.7nm and no yellow luminescence bands are observed.The AlN buffer layers can effectively block the additional reaction between Si substrate and reactive gas during the GaN growth,and reduce the residual stress of the GaN thick film.