Abstract Through transmission electron microscopy and related techniques, we performed structural evaluation of low-temperature grown (LTG) InGaAs crystals on (0 0 1) InP substrates. These crystals were grown at a substrate temperature of 200–250 °C. The results revealed that As precipitates (diameter: 7–15 nm) are generated in undoped InGaAs crystals (mainly near the interface between the epi-layer and the substrate) after annealing at 550 °C for 1 h. However, no precipitates were observed in Be-doped LTG InGaAs crystals before and after annealing. Moreover, in the case of Be-doped LTG-InGaAs crystals highly mismatched with the InP substrate, we observed no preferential generation of precipitates at the core of the misfit dislocations. Based on these findings, the generation mechanism of the precipitates in undoped LTG-InGaAs crystals during the annealing process and physical origin for the absence of precipitates in Be-doped LTG-InGaAs crystals after the annealing are discussed. Apart from the precipitates, we have also found that surface defects elongated in the [1 1 0] direction are formed in the InGaAs crystal, which are presumably generated by the evaporation of As-atoms from the surface during annealing.

中文翻译：

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(001) InP 衬底上低温生长的 InGaAs 晶体的结构评估

摘要 通过透射电子显微镜和相关技术，我们对 (0 0 1) InP 衬底上的低温生长 (LTG) InGaAs 晶体进行了结构评估。这些晶体在 200-250 °C 的衬底温度下生长。结果表明，在 550°C 下退火 1 小时后，未掺杂的 InGaAs 晶体（主要在外延层和衬底之间的界面附近）中会产生 As 沉淀物（直径：7-15 nm）。然而，在退火前后在掺 Be 的 LTG InGaAs 晶体中没有观察到沉淀物。此外，在掺 Be 的 LTG-InGaAs 晶体与 InP 衬底高度失配的情况下，我们观察到在失配位错的核心处没有优先生成沉淀物。基于这些发现，讨论了退火过程中未掺杂LTG-InGaAs晶体中析出物的产生机制以及退火后Be掺杂LTG-InGaAs晶体中不存在析出物的物理原因。除了析出物，我们还发现在[1 1 0]方向上拉长的表面缺陷在InGaAs晶体中形成，这可能是由于退火过程中As原子从表面蒸发而产生的。