Qiu Y, Bender H, Richard O, Kim M-S, Van Besien E, Vos I, de Potter de ten Broeck M, Mocuta D, Vandervorst W
1] Imec, Kapeldreef 75, Leuven, Belgium [2] Instituut Kern-en Stralings Fysika, K.U.Leuven, Leuven, Belgium.
Imec, Kapeldreef 75, Leuven, Belgium.
Sci Rep. 2015 Aug 4;5:12692. doi: 10.1038/srep12692.
Silicon crystallizes in the diamond-cubic phase and shows only a weak emission at 1.1 eV. Diamond-hexagonal silicon however has an indirect bandgap at 1.5 eV and has therefore potential for application in opto-electronic devices. Here we discuss a method based on advanced silicon device processing to form diamond-hexagonal silicon nano-ribbons. With an appropriate temperature anneal applied to densify the oxide fillings between silicon fins, the lateral outward stress exerted on fins sandwiched between wide and narrow oxide windows can result in a phase transition from diamond-cubic to diamond-hexagonal Si at the base of these fins. The diamond-hexagonal slabs are generally 5-8 nm thick and can extend over the full width and length of the fins, i.e. have a nano-ribbon shape along the fins. Although hexagonal silicon is a metastable phase, once formed it is found being stable during subsequent high temperature treatments even during process steps up to 1050 ºC.
硅以金刚石立方相结晶，在1.1电子伏特处仅显示出微弱的发射。然而，金刚石六方相硅在1.5电子伏特处具有间接带隙，因此在光电器件中有应用潜力。在此，我们讨论一种基于先进硅器件加工的方法来形成金刚石六方相硅纳米带。通过施加适当的温度退火以致密化硅鳍片之间的氧化物填充物，施加在夹在宽和窄氧化物窗口之间的鳍片上的横向向外应力可导致这些鳍片底部的硅从金刚石立方相转变为金刚石六方相。金刚石六方相平板通常厚5 - 8纳米，并且可以在鳍片的整个宽度和长度上延伸，即沿鳍片具有纳米带形状。尽管六方相硅是亚稳相，但一旦形成，发现在随后的高温处理期间甚至在高达1050℃的工艺步骤中它都是稳定的。
