β-Ga_2O_3单晶腐蚀坑形貌研究
|
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.
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
[1]SUZUKI R,NAKAGOMI S,KOKUBUN Y,et al.Enhancement of responsivity in solar-blind β-Ga2O3 photodiodes with a Au Schottky contact fabricated on single crystal substrates by annealing[J].Applied Physics Letters,2009,94(22):222102-1-222102-3.
[2]SHIMAMURA K,VILLORA E G,DOMEN K,et al.Epitaxial growth of GaN on(100) β-Ga2O3 substrates by metalorganic vapor phase epitaxy[J].Japanese Journal of Applied Physics,2005,44(1):L7-L8.
[3]HIGASHIWAKI M,KONISHI K,SASAKI K,et al.Temperature-dependent capacitance-voltage and current-voltage characteristics of Pt/Ga2O3(001)Schottky barrier diodes fabricated on n-Ga2O3drift layers grown by halide vapor phase epitaxy[J].Applied Physics Letters,2016,108(13):133503-1-133503-3.
[4]WONG M H,SASAKI K,KURAMATA A,et al.Field-plated Ga2O3 MOSFETs with a breakdown voltage of over 750 V[J].IEEE Electron Device Letters,2016,37(2):212-215.
[5]HIDEO A,KENGO N,HIDETOSHI T,et al.Growth of β-Ga2O3 single crystals by the edge-defined,film fed growth method[J].Japanese Journal of Applied Physics,2008,47(11):8506-8509.
[6]ZHOU W,XIA C T,SAI Q L,et al.Controlling n-type conductivity of β-Ga2O3 by Nb doping[J].Applied Physics Letters,2017,111(24):242103-1-242103-4.
[7]GALAZKA Z,IRMSCHER K,UECKER R,et al.On the bulk β-Ga2O3 single crystals grown by the Czochralski method[J].Journal of Crystal Growth,2014,404:184-191.
[8]GREEN A J,CHABAK K D,HELLER E R,et al.3.8-MV/cm breakdown strength of MOVPE-grown Sn-doped β-Ga2O3 MOSFETs[J].IEEE Electron Device Letters,2016,37(7):902-905.
[9]KURAMATA A,KOSHI K,WATANABE S,et al.Highquality β-Ga2O3 single crystals grown by edge-defined film-fed growth[J].Japanese Journal of Applied Physics,2016,55(12):1202A2-1-1202A2-6.
[10]KO Y H,BAE S B,KIM S B,et al.Wafer-scale crack-free AlGaN on GaN through two-step selective-area growth for optically pumped stimulated emission[J].Journal of Crystal Growth,2016,445:78-83.
[11]ZHANG S N,LIAN X Z,MA Y CM,et al.Growth and characterization of 2-inch high quality β-Ga2O3 single crystals grown by EFG method[J].Journal of Semiconductors,2018,39(8):27-31.
[12]练小正,张胜男,程红娟,等.大尺寸晶片的机械剥离及性能[J].微纳电子技术,2018,55(6):450-454.
[2]SHIMAMURA K,VILLORA E G,DOMEN K,et al.Epitaxial growth of GaN on(100) β-Ga2O3 substrates by metalorganic vapor phase epitaxy[J].Japanese Journal of Applied Physics,2005,44(1):L7-L8.
[3]HIGASHIWAKI M,KONISHI K,SASAKI K,et al.Temperature-dependent capacitance-voltage and current-voltage characteristics of Pt/Ga2O3(001)Schottky barrier diodes fabricated on n-Ga2O3drift layers grown by halide vapor phase epitaxy[J].Applied Physics Letters,2016,108(13):133503-1-133503-3.
[4]WONG M H,SASAKI K,KURAMATA A,et al.Field-plated Ga2O3 MOSFETs with a breakdown voltage of over 750 V[J].IEEE Electron Device Letters,2016,37(2):212-215.
[5]HIDEO A,KENGO N,HIDETOSHI T,et al.Growth of β-Ga2O3 single crystals by the edge-defined,film fed growth method[J].Japanese Journal of Applied Physics,2008,47(11):8506-8509.
[6]ZHOU W,XIA C T,SAI Q L,et al.Controlling n-type conductivity of β-Ga2O3 by Nb doping[J].Applied Physics Letters,2017,111(24):242103-1-242103-4.
[7]GALAZKA Z,IRMSCHER K,UECKER R,et al.On the bulk β-Ga2O3 single crystals grown by the Czochralski method[J].Journal of Crystal Growth,2014,404:184-191.
[8]GREEN A J,CHABAK K D,HELLER E R,et al.3.8-MV/cm breakdown strength of MOVPE-grown Sn-doped β-Ga2O3 MOSFETs[J].IEEE Electron Device Letters,2016,37(7):902-905.
[9]KURAMATA A,KOSHI K,WATANABE S,et al.Highquality β-Ga2O3 single crystals grown by edge-defined film-fed growth[J].Japanese Journal of Applied Physics,2016,55(12):1202A2-1-1202A2-6.
[10]KO Y H,BAE S B,KIM S B,et al.Wafer-scale crack-free AlGaN on GaN through two-step selective-area growth for optically pumped stimulated emission[J].Journal of Crystal Growth,2016,445:78-83.
[11]ZHANG S N,LIAN X Z,MA Y CM,et al.Growth and characterization of 2-inch high quality β-Ga2O3 single crystals grown by EFG method[J].Journal of Semiconductors,2018,39(8):27-31.
[12]练小正,张胜男,程红娟,等.大尺寸晶片的机械剥离及性能[J].微纳电子技术,2018,55(6):450-454.