摘要
详细介绍了(100)、(010)和(■01)三种不同晶面的β-Ga_2O_3单晶腐蚀坑形貌状态及不同形貌的演变过程。所用β-Ga_2O_3单晶样品均为导模法(EFG)制备,且经过研磨、化学机械抛光(CMP),表面质量良好。以质量分数为85%的分析纯H_3PO_4溶液为腐蚀液,腐蚀时间为1.5 h,腐蚀温度为90℃时,(100)、(010)和(■01)晶面腐蚀坑密度分别约为6.9×10~(4 )cm~(-2)、2.3×10~(4 )cm~(-2)和7.7×10~(4 )cm~(-2)。通过光学显微镜和扫描电子显微镜(SEM)观察,结果表明(100)面腐蚀坑形状为非对称六边形,(010)面腐蚀坑形貌为菱形,(■01)面腐蚀坑形貌为倾斜的五边形,并确定了(100)面、(010)面、(■01)面的最终腐蚀坑状态,腐蚀坑的不同形状可能与不同晶向β-Ga_2O_3表面状态的耐化学腐蚀差异有关。
The states and evolution process of different morphologies of the etch-pits on (100),(010) and (■01) crystal planes of β-Ga_2O_3 single crystal were investigated in detail.The β-Ga_2O_3 single crystal samples were prepared by edge-defined film fed growth(EFG).And then all the samples were grinded and polished by chemically mechanical polishing(CMP)to achieve high surface quality.After the crystal planes were corroded by analytical H_3PO_4 solution (mass fraction is 85%) at 90℃ for 1.5 h,the densities of the etch-pits for (100),(010) and (■01)crystal planes were observed to be approximately 6.9×10~4cm~(-2),2.3×10~4cm~(-2),and 7.7×10~4cm~(-2),respectively.The results of the optical microscopy and scanning electron microscopy(SEM)demonstrate different morphologies of the etch-pits i.e.asymmetric hexagonal shape for (100),diamond shape for (010) and tilted pentagonal shape for (■01).Besides,the finally states of the etch-pits for(100),(010)and (■01) crystal planes were determined,and the diverse shapes of the etch-pits could be associated with the difference in the resistance to the chemical corrosion due to the surface states on different orientations of β-Ga_2O_3 single crystals.
引文
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