Liu Chie-Sheng, Chou Li-Wei, Hong Lu-Sheng, Jiang Jyh-Chiang
Department of Chemical Engineering, National Taiwan University of Science and Technology, 43, Keelung Road, Section 4, Taipei, 106, Taiwan.
J Am Chem Soc. 2008 Apr 23;130(16):5440-2. doi: 10.1021/ja710802s. Epub 2008 Mar 26.
This paper describes the initial reaction kinetics of Ge deposition after exposure of Si(100)-2 x 1 to GeH4 in a UHV-CVD system. The rate of Ge growth, especially at the wetting layer stage, was investigated using in situ X-ray photoelectron spectroscopy to measure the Ge signal at the onset of deposition. A kinetic analysis of the initial growth of the Ge wetting layer at temperatures ranging from 698 to 823 K revealed an activation energy of 30.7 kcal/mol. Density functional theory calculations suggested that opening of the Si dimer--with a closely matching energy barrier of 29.7 kcal/mol, following hydrogen atom migration--was the rate controlling step for the incorporation of a GeH2 unit into the lattice to complete the growth of the Ge wetting layer after dissociative adsorption of GeH4.
本文描述了在超高真空化学气相沉积（UHV-CVD）系统中，将Si(100)-2×1暴露于GeH₄后Ge沉积的初始反应动力学。利用原位X射线光电子能谱在沉积开始时测量Ge信号，研究了Ge的生长速率，特别是在润湿层阶段的生长速率。对在698至823 K温度范围内Ge润湿层的初始生长进行动力学分析，结果显示活化能为30.7 kcal/mol。密度泛函理论计算表明，在氢原子迁移之后，Si二聚体的打开——其能量势垒与29.7 kcal/mol紧密匹配——是在GeH₄解离吸附后，将GeH₂单元并入晶格以完成Ge润湿层生长的速率控制步骤。
