Control of local surface strain by using EB process

通过控制化学束外延中砷/磷的供给，研究了自组织InGaAs点的原位组成变化。由于点中的砷/磷原子被环境中的磷/砷取代，表面结构根据砷/磷暴露从InGaAs点转变为InGaAsP平面，反之亦然。在点结构和平面之间的过渡表面进行亚稳态和非原位观察，以了解点的形成过程。结果表明，在网点形成过程中，发育良好的网点密度（而非致密网点的大小）呈增加趋势。介绍了两种利用砷/磷替代技术原位修饰点状结构的新方法。对于InAs点改造，较小的InAs点消失，形成较大的InAs点。在脉冲AsH_3暴露逐步点状重整过程中对铟或镓的额外供应的检验中，只有在添加铟的情况下，点状重整才会由于过度应变而发生聚并。将砷化镓或铟化磷暴露于氟的电子回旋等离子体中制备了氟化镓或氟化铟薄膜。氟化膜对电子束敏感，在电子束照射下发生分解反应。

In situ composition change of self-organized InGaAs dots has been investigated by means of the control of arsenic/phosphorus supply in chemical beam epitaxy. Due to the replacement of arsenic/phosphorus atoms in the dots by ambient phosphorus/arsenic, surface structure changes from the InGaAs dots to an InGaAsP flat surface and vice versa according to the arsenic/phosphorus exposure. Transitional surfaces between the dot structure and a flat surface were metastabilized and observed ex situ to figure out the dot formation process. It was found that the density of well-developed dots (not the size of dense dots) was increasing during the dot formation. Two new approaches to modifying the dot strucure in situ by using the arsenic/phosphorus replacement technique were demonstrated. For InAs dot reformation, smaller InAs dots disappeared and larger InAs dots were formed instead. In the examination of additional suppy of indium or gallium during step-by-step dot reformation with pulse AsH_3 exposure, the coalescence of dots occurred due to excess strain only in the case of indium addition. Thin films of gallium flouride or indium flouride were fabricated by exposuring GaAs or InP to electron cyclotron plasma of flourine. The flouride films were found to be electron beam (EB) sensetive, that the decomposition reaction occurs by EB irradiation.