Time multiplexed deep reactive ion etching of germanium and silicon-A comparison of mechanisms and application to x-ray optics.

Although the mechanisms of deep reactive ion etching (DRIE) of silicon have been reported extensively, very little by comparison has been discussed concerning DRIE of germanium. By directly comparing silicon and germanium etching in a time multiplexed DRIE process, the authors extract significant differences in etch mechanisms from a design of experiment and discuss how these differences are relevant to the design and fabrication of silicon and germanium collimating channel array x-ray optics. The differences are illuminated by characteristics such as reactive ion etching (RIE)-lag, aspect ratio dependent etching, and sidewall passivation.