热处理对非掺杂半绝缘LEC GaAs电特性的影响

The Annealing Effects on Electronic Properties for Undoped Semi-insulating LECGaAs

对非掺杂（ＮＤ）半绝缘（ＳＩ）液封直拉（ＬＥＣ）ＧａＡｓ单晶在 ９５０℃下进行了不同 Ａｓ压的热处理，研究了热处理对材料电特性的影响．发现在９５０℃温度和低Ａｓ压条件下 进行１４ｈ热处理，可在样品中引入本征受主缺陷，并导致体霍尔迁移率大幅下降和体电阻 率明显增加．这些受主缺陷的产生是由于高温和低 ＡＳ压条件下 ＧａＡｓ晶体中发生 Ａｓ间隙 原子的外扩散．提高热处理过程中的Ａｓ气压，可抑制这些受主缺陷的产生和电参数的变化．

Annealing has been carried out at 950℃ under various As pressure for undoped (ND) semiinsulating (SI) LEC GaAs. The effects of the annealing on the electrical properties are investigated. It is found that after the annealing at 950℃ for l4 h under low As pressure, the samples' Hall mobility decreases and the resistivity increases dramatically. These changes in electrical properties are due to the generation of intrinsic acceptor de- fects, which originates from the outdiffusion of As interstitial at high temperature. The generation of the intrinsic defects and the changes of electrical properties can be suppressed by increasing the applied As pressure during annealing.