导模法和温度梯度法生长r面蓝宝石(英文)

r面(0112)蓝宝石晶体可用作制备非极性GaN薄膜的衬底。采用温度梯度法(temperature gradient technique,TGT)和导模法(edge-defined film-fed crystal growth,EFG)生长了质量良好的r面蓝宝石晶体。利用双晶衍射、光学显微镜、光谱仪观察和分析了晶体的结构和缺陷。结果表明:TGT法生长的r蓝宝石晶体的双晶摇摆曲线对称性好,半高宽值仅为18 rad.s,位错密度为4×103 cm-2,透过率达83%,晶体质量好。与TGT法相比,EFG法生长的r面蓝宝石晶体的结构完整性较差,位错密度为5×105 cm-2,透过率仅为75%。但是EFG法具有晶体生长速度快,后期加工成本低的优点。

(011¯2) r-plane sapphire is usually used as a substrate for growing nonpolar (112¯0) α-plane GaN film, r-plane sapphires with good quality were successfully grown by temperature gradient technique (TGT) and edge-defined film-fed crystal growth (EFG) methods. The properties of the sapphires were measured by double crystal diffractometry, optical microscopy and optical spectrometry. The results show that the sapphire grown by the TGT method has a dislocation density of 4 × l0³ cm^-2 and transmittance of 83%, and the full width at half maximum of the double crystal rocking curve is only 18 rad&middots. The crystal is higher quality than the EFG sapphire. The dislocation density and transmittance of the sapphire grown by the EFG method are 5 × l0⁵cm^-2 and 75%, respectively. However, sapphires can be grown faster using the EFG method, which decreases the processing cost in the production of substrate.