Reduction of Defects in Silicon-on-Sapphire Material by Ion Implantation of Germanium for Application to Bipolar Technology

为了扩大应用范围以包括双极器件，需要大幅减少蓝宝石上硅材料中的缺陷。在过去的几年里，通过注入硅对硅层进行区域非晶化和固相外延再生长可以降低硅覆盖层中的缺陷密度。然而，大规模使用这一工艺的一个障碍是，它需要注入硅-29离子以避免污染物的引入。另一个障碍是，晶圆必须冷却到液氮温度。该项目将研究锗注入和固相外延工艺的效果，这可能是大规模晶圆改进的可行性。注入锗是有利的，因为非晶化的剂量几乎可以比硅低一个数量级，而且不需要液氮冷却。

Substantial reduction of defects in silicon-on-sapphire material is required to broaden the range of applications to include bipolar devices. During the past few years, it has been shown that regional amorphization of the silicon layer by implantation of silicon and solid phase epitaxy regrowth can reduce the defect density in the silicon overlayer. However, one obstacle to large scale use of this process is that it requires implantation of silicon-29 ions to avoid introduction of contaminants. Another obstacle is that the wafers must be cooled to liquid nitrogen temperature. This program will study the effect of a germanium implantation and solid phase epitaxy process which could be feasible for large scale wafer improvement. Implantation of germanium is advantageous because amorphization can be achieved with a dose almost an order of magnitude lower than required with silicon and without liquid nitrogen cooling.