直拉硅单晶的杂质工程：氮和锗杂质共掺的效应及其应用

450 mm Czochralski silicon (Cz-Si) wafers will gradually become the base material for integrated circuits. Unfortunately, the traditional Cz growth technology based on Dash necking process will be not vialbe for the growth of 450 mm Cz-Si crystals heavier than 400 kilograms (Kg). Moreover, 450 mm Cz-Si is faced with new challenges in the regards of mechanical strength, cantrol and application of defects. Addressing the aforementioned critical issues, the present project will perfrom prospective research. For the first time it proposes a new type of Cz-Si that is co-doped with nitrogen (N) and germanium (Ge) impurities, aiming at synergistically exerting the advantages of both N- and Ge-doping while suppressing the disadvantages of either N or Ge individual-doping. The effects of N and Ge co-doping on the mechanical strength, oxygen precipitation and its associated IG, evolution of point defects and the formation of other defects will be systematically investigated and the underlying mechanisms will be elucidated. Based on the consequent results, the project will develop a Cz growth technology based on the N and Ge co-doped seed that needs no Dash necking process. Such a new Cz growth technology will be viable for 450 mm Cz-Si crystals heavier than 400 Kg. On the other hand, the project will provide the fundamental knowledge of manipulating defects for the performance improvement of 450 mm Cz-Si.

450 mm直拉硅单晶将逐渐成为集成电路的基础材料。然而，传统的基于Dash缩颈工艺的直拉生长技术将不再适用于重量超过400公斤的450 mm直拉硅单晶的生长。此外，450 mm直拉硅单晶还在机械强度、缺陷控制和利用等方面面临着新的挑战。 本项目针对450 mm直拉硅单晶所面临的上述关键问题，开展先导性的应用基础研究。在国际上首次提出一类氮和锗杂质共掺的新型直拉硅单晶，以发挥掺氮和掺锗两者的优点、并克服单一掺氮或掺锗的缺点。项目将系统地研究氮和锗杂质共掺对直拉硅单晶的机械强度、氧沉淀及与之相关的内吸杂、点缺陷演变和其它缺陷的行为等多方面的影响和作用规律，并阐明相应的物理机制。在此基础上，一方面发展出无需Dash缩颈工艺的无位错直拉硅单晶生长的新技术，可用于以后生长重量超过400公斤的450 mm直拉硅单晶；另一方面提出控制和利用缺陷的技术原理，可用于以后提高450 mm直拉硅单晶的性能。