Bollani M, Bonera E, Chrastina D, Fedorov A, Montuori V, Picco A, Tagliaferri A, Vanacore G, Sordan R
Nanoscale Res Lett. 2010 Sep 7;5(12):1917-20. doi: 10.1007/s11671-010-9773-0.
SiGe islands have been proposed for applications in the fields of microelectronics, optoelectronics and thermoelectrics. Although most of the works in literature are based on MBE, one of the possible advantages of low-energy plasma-enhanced chemical vapor deposition (LEPECVD) is a wider range of deposition rates, which in turn results in the possibility of growing islands with a high Ge concentration. We will show that LEPECVD can be effectively used for the controlled growth of ordered arrays of SiGe islands. In order to control the nucleation of the islands, patterned Si (001) substrates were obtained by e-beam lithography (EBL) and dry etching. We realized periodic circular pits with diameters ranging from 80 to 300 nm and depths from 65 to 75 nm. Subsequently, thin films (0.8-3.2 nm) of pure Ge were deposited by LEPECVD, resulting in regular and uniform arrays of Ge-rich islands. LEPECVD allowed the use of a wide range of growth rates (0.01-0.1 nm s(-1)) and substrates temperatures (600-750°C), so that the Ge content of the islands could be varied. Island morphology was characterized by AFM, while μ-Raman was used to analyze the Ge content inside the islands and the composition differences between islands on patterned and unpatterned areas of the substrate.
硅锗岛已被提议应用于微电子、光电子和热电领域。尽管文献中的大多数工作都是基于分子束外延（MBE），但低能等离子体增强化学气相沉积（LEPECVD）的一个可能优势是具有更广泛的沉积速率范围，这反过来又使得生长具有高锗浓度的岛成为可能。我们将证明LEPECVD可有效地用于可控生长有序排列的硅锗岛阵列。为了控制岛的成核，通过电子束光刻（EBL）和干法蚀刻获得了图案化的Si（001）衬底。我们实现了直径范围为80至300纳米、深度为65至75纳米的周期性圆形坑。随后，通过LEPECVD沉积了纯锗的薄膜（0.8 - 3.2纳米），从而得到了规则且均匀的富锗岛阵列。LEPECVD允许使用广泛的生长速率（0.01 - 0.1纳米每秒）和衬底温度（600 - 750°C），这样岛中的锗含量就可以变化。通过原子力显微镜（AFM）对岛的形态进行了表征，而μ - 拉曼光谱则用于分析岛内部的锗含量以及衬底图案化区域和未图案化区域上岛之间的成分差异。
