A, M, Prokhorov General Physics Institute of RAS, 38 Vavilov Street, 119991 Moscow, Russia.
Nanoscale Res Lett. 2011 Sep 5;6(1):522. doi: 10.1186/1556-276X-6-522.
Issues of morphology, nucleation, and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (≲600°C) and high (≳600°C) temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts--pyramids and wedges-- are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001) surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001) quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature.
考虑了超高真空分子束外延在 Si(001)表面沉积的 Ge 团簇阵列的形态、成核和生长问题。通过高分辨率扫描隧道显微镜研究了在低温（≲600°C）和高温（≳600°C）下沉积 Ge 时量子点成核的差异。提出了两种 Ge 棚--金字塔和楔形--生长的原子模型。探索了低温下 Ge QD 阵列的生长循环。讨论了降低阵列形成温度的问题，重点是整个过程与 CMOS 的兼容性；特别关注在 Si(001)表面预生长清洁过程中降低处理温度的方法，这是 Ge/Si(001)量子点密集阵列形成过程的关键和最高温度阶段。清洁 Si 表面的准备温度，其最后一个高温步骤通常直接在 MBE 腔室内进行，就在结构沉积之前，这决定了基于 Ge-QD-阵列器件的形成过程与 CMOS 制造周期的兼容性。在初步清洁过程中湿化学蚀刻的最后阶段对硅表面进行氢化，被提议作为有效降低硅片预生长退火温度的可能方法。
