绝缘体上全局应变硅晶圆的制备和表征

Fabrication and Characterization of Global Strained Si on Insulator

首先使用改良型Ge浓缩法制备了绝缘体上锗硅圆片,然后在超薄弛豫SiGe层上,利用超高真空化学气相沉积法外延了单晶硅薄膜,获得一系列不同厚度的6寸绝缘体上应变硅晶圆。结果表明应变硅薄膜完整、均匀、表面平整且晶体质量良好,获得样品中顶层硅最大应力值达2.22 GPa。应用临界厚度理论对样品厚度和应变值之间的关系进行了分析,发现本实验所得样品在超过临界厚度3倍之后会发生应变弛豫。

Firstly, SiGe on insulator （SGOI） wafers were fabricated by modified Ge condensation technology, then single crystal Si films were epitaxially deposited on the ultra-thin relaxed SiGe layer by ultra-high vacuum chemical vapor deposition （UHVCVD）. Finally, a series of strained Si wafers with different thickness were obtained. The results indicate that the strained Si layers were complete and uniform, with a flat surface and high quality crystal lattice. The highest stress attained 2.22 GPa. The relation between strain and thickness was analyzed using theory of critical thickness, and it was found that the strained Si samples in this paper did not relax until the thickness reached triple critical one.