梯度铝镓氮缓冲层对氮化镓外延层性质的影响  

Effects of Step-graded Al_xGa_(1-x)N Buffer on Properties of GaN Films

作　　者：李宝珠[1] 黄振[1] 邓高强[1] 董鑫[1] 张源涛[1] 张宝林[1] 杜国同[1] 

机构地区：[1]集成光电子国家重点联合实验室吉林大学电子科学与工程学院,吉林长春130012

出　　处：《发光学报》2017年第6期780-785,共6页Chinese Journal of Luminescence

基　　金：国家自然科学基金(61274023;61106003;61376046;61674068);国家重点研发计划(2016YFB0400103);吉林省科技发展计划(20130204032GX;20150519004JH;20160101309JC);教育部新世纪人才计划(NCET13-0254)资助项目~~

摘　　要：采用金属有机物化学气相沉积系统在硅面碳化硅衬底的(0001)面上生长氮化铝缓冲层,并通过改变3层梯度铝镓氮(Al_xGa_(1-x)N:x=0.8,0.5,0.2)缓冲层的生长温度和氨气流量,制备出了高质量的氮化镓外延层。分别采用X射线衍射、原子力显微镜、光致发光谱和拉曼光谱对氮化镓外延层进行表征。实验结果表明,随着氮化镓外延层中张应力的降低,样品的晶体质量、表面形貌和光学质量都有显著提高。在最优的梯度铝镓氮缓冲层的生长条件下,氮化镓外延层中的应力值最小,氮化镓(0002)和(1012)面的摇摆曲线半峰宽分别为191 arcsec和243 arcsec,薄膜螺位错密度和刃位错密度分别为7×10~7cm^(-2)和3.1×108cm^(-2),样品表面粗糙度为0.381 nm。这说明梯度铝镓氮缓冲层可以改变氮化镓外延层的应力状态,显著提高氮化镓外延层的晶体质量。High-quality GaN films were grown on Si-plane 6H-SiC （0001） substrates with AlN buff- er and step-graded A1GaN （A1xGa1-xN ： x = 0.8,0.5,0.2） buffer with different growth temperature and NH3 flux by metal-organic chemical vapor deposition （MOCVD）. The properties of GaN films were examined by X-ray diffraction, atomic force microscopy, room temperature photoluminescence spectra and Raman spectra. Experimental results show that the lower tensile stress in the GaN films, the higher the crystallinity, surface morphologies and optical properties of the GaN films. Under the optimum conditions of A1GaN buffer, the stress value of GaN films is reduced to its minimum. The co-rocking curves full-width at half-maximum （FWHM） of the （0002） and （10（2） planes are amel- iorated to 191 and 243 arcsec, respectively. The densities of screw and edge dislocations decrease to the best values of 7 × 10^7 and 3. 1 × 10^8 cm×-2 The root-mean-squared roughness value is 0. 381 nm. It shows that the step-graded A1GaN buffer can change stress state in GaN fihns effectively and improve the crystallinity of GaN films significantly.

关 键 词：氮化镓 梯度铝镓氮缓冲层 晶体质量 应力 

分 类 号：TP394.1[自动化与计算机技术—计算机应用技术] TN484.4[自动化与计算机技术—计算机科学与技术]