GaAs衬底上生长的GaInP_2外延单晶薄膜的杂质污染研究

STUDIES ON CONTAMINANTS IN GaInP 2 EPILAYERS GROWN ON GaAs

各种外延技术已被用来在ＧａＡｓ衬底上生长ＧａｘＩｎ１－ｘＰ外延单晶薄膜（ＧａＩｎＰ２／ＧａＡｓ）．很多文献认为，在ＧａＩｎＰ２／ＧａＡｓ生长过程中会被Ｃ杂质污染．我们用高灵敏的ＣＡＭＥＣＡＩＭＳ４Ｆ型二次离子质谱仪直接测量的结果表明，污染ＧａＩｎＰ２／ＧａＡｓ的微量杂质是Ｓｉ，而不是Ｃ．由ＧａＩｎＰ２／ＧａＡｓ在１．１７ｅＶ附近的光致发光峰的峰值随激发强度的变化形状表明了它应属于施主－受主对复合发光．进一步分析表明，施主为处在Ｇａ格位上的Ｓｉ杂质（ＳｉＧａ），受主为Ｇａ空位（ＶＧａ）．

Various epitaxial techniques have been utilized for growing Ga x In 1-x P epilayers on GaAs substrates (GaInP 2/GaAs). Impurities in the epitaxial GaInP 2/GaAs seriously effect on its optical and electrical properties. Therefore, it is important to demonstrate what kinds of impurities are common contaminants in epitaxial GaInP 2/GaAs. A lot of literatures considered C as a contaminant during growing GaInP 2/GaAs epilayers. Our measurements with CAMECA IMS 4F secondary ion mass spectrometer indicated that there exists contaminant Si instead of C in GaInP 2/GaAs samples. The shape for the variation of excitation intensity versus peak energy of the photoluminescence (PL) emission nearby 1.17eV in GaInP 2/GaAs samples illustrated that 1.17eV PL emission could be considered as a donor acceptor pair (DAP) transition, and furthermore, as a DAP transition of Si Ga V Ga , where Si Ga is a silicon donor on a gallium sublattice site and V Ga is a gallium vacancy acceptor.