Impacts of excimer laser annealing on Ge epilayer on Si

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• 作者：Zhiwei Huang ; Yichen Mao ; Xiaohui Yi ; Guangyang Lin ; Cheng Li…
• 刊名：Applied Physics A
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：123
• 期：2
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Condensed Matter Physics; Optical and Electronic Materials; Nanotechnology; Characterization and Evaluation of Materials; Surfaces and Interfaces, Thin Films; Operating Procedures, Materials Treatment
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-0630
• 卷排序：123

文摘

The impacts of excimer laser annealing on the crystallinity of Ge epilayers on Si substrate grown by low- and high-temperature two-step approach in an ultra-high vacuum chemical vapor deposition system were investigated. The samples were treated by excimer laser annealing (ELA) at various laser power densities with the temperature above the melting point of Ge, while below that of Si, resulting in effective reduction of point defects and dislocations in the Ge layer with smooth surface. The full-width at half-maximum (FWHM) of X-ray diffraction patterns of the low-temperature Ge epilayer decreases with the increase in laser power density, indicating the crystalline improvement and negligible effect of Ge–Si intermixing during ELA processes. The short laser pulse time and large cooling rate cause quick melting and recrystallization of Ge epilayer on Si in the non-thermal equilibrium process, rendering tensile strain in Ge epilayer as calculated quantitatively with thermal mismatch between Si and Ge. The FWHM of X-ray diffraction patterns is significantly reduced for the two-step grown samples after treated by a combination of ELA and conventional furnace thermal annealing, indicating that the crystalline of Ge epilayer is improved more effectively with pre- annealing by excimer laser.