二氧化硅上锗锡合金的晶化机理研究

Silicon-based integrated optoelectronics is a research topic of considerable interest in information science and technology during recent years. 3D optoelectronic integration, meanwhile, is a new trend in the future development of silicon-based integrated optoelectronics. As a novel group-IV semiconductor, germanium-tin alloy, which has direct bandgap and high carrier mobility, can be used to fabricate both Si-based opto- and micro-electronic devices, such as Si-based lasers and high-performance transistors. Therefore, it is an optimal material for photonic-electronic integration. With a view to growing germanium-tin alloy for Si-based 3D photonic-electronic integration, this program will explore the growth methods of solid-phase crystallization and metal-induced crystallization for germanium-tin alloy. Tin can not only enhance crystallization without introducing deep-level defect centers, but also adjust the material properties. By investigating the crystallization mechanism of germanium-tin alloy, the program aims to grow high-crystalline-quality germanium-tin alloys on amorphous silicon-dioxide layers through controlling the nucleate and growth rate of the alloy, which will lay a solid foundation for the development of silicon-based 3D photonic-electronic integration.

硅基集成光电子学是近年来信息科学与技术领域的一个研究热点。未来硅基集成光电子技术一个新的发展趋势是三维（3D）光电集成。锗锡合金作为一种新颖的IV族半导体，具有直接带隙和高载流子迁移率，可用于制作硅基激光器和高性能晶体管等硅基光电子和微电子器件，非常适合于光电集成。本项目以制备适用于硅基3D光电集成的锗锡材料为目标，探索锗锡合金固相晶化和锡诱导晶化的制备方法。这两种方法的主要优势有：锡既可以增强晶化，又不会在锗锡中引入深能级缺陷中心，而且还可以调节材料的性质。通过本项目研究，我们将揭示锗锡合金的晶化机理，获得控制锗锡合金成核和生长速率的方法，在二氧化硅非晶层上制备出高晶体质量的锗锡合金，为硅基3D光电集成的发展奠定基础。

Ge1-xSnx合金具有直接带隙和高载流子迁移率，可用于制作Si基激光器和高性能晶体管等Si基光电子和微电子器件，非常适合于光电集成。针对未来微电子技术将沿3D集成方向发展的趋势，本项目以制备适用于Si基3D光电集成的Ge1-xSnx合金为目标，重点研究在SiO2上非晶Ge1-xSnx合金的晶化机理，同时研究晶化的Ge1-xSnx合金的材料特性。本项目研究发现,生长温度TG和退火温度TA都会影响Ge0.995Sn0.005的表面形貌和应变情况。当生长温度TG在220 ℃ ~500 ℃时，随着生长温度的升高，GeSn表面粗糙度越来越大，并且残留压应变越来越小。当退火温度低于600 ℃时，表面粗糙度和表面应变情况几乎没有变化。而当温度高于600 ℃时，随这退火温度的提高，表面粗糙度急剧增大，并且残留应变逐渐得到释放。此外，本项目在Si衬底上，采用磁控溅射沉积出了单晶Ge1-x-ySixSny合金薄膜，并研究了其组分、晶格常数、晶格质量、热稳定性以及光吸收特性。