Growth of Cubic Silicon Carbide on Oxide Using Polysilicon as a Seed Layer for Micro-Electro-Mechanical Machine Applications


Frewin, C. L., Locke, C., Wang, J., Spagnol, P., & Saddow, S. E. (2009). Growth of cubic silicon carbide on oxide using polysilicon as a seed layer for micro-electro-mechanical machine applications. Journal of Crystal Growth, 311(17), 4179-4182.


The growth of highly oriented 3C–SiC directly on an oxide release layer, composed of a 20-nm-thick poly-Si seed layer and a 550-nm-thick thermally deposited oxide on a (1 1 1)Si substrate, was investigated as an alternative to using silicon-on-insulator (SOI) substrates for freestanding SiC films for MEMS applications. The resulting SiC film was characterized by X-ray diffraction (XRD) with the X-ray rocking curve of the (1 1 1) diffraction peak displaying a FWHM of 0.115° (414″), which was better than that for 3C–SiC films grown directly on (1 1 1)Si during the same deposition process. However, the XRD peak amplitude for the 3C–SiC film on the poly-Si seed layer was much less than for the (1 1 1)Si control substrate, due to slight in-plane misorientations in the film. Surprisingly, the film was solely composed of (1 1 1) 3C–SiC grains and possessed no 3C–SiC grains oriented along the 〈3 1 1〉 and 〈1 1 0〉 directions which were the original directions of the poly-Si seed layer. With this new process, MEMS structures such as cantilevers and membranes can be easily released leaving behind high-quality 3C–SiC structures.

Keywords: A1. X-ray diffraction, A1. Characterization, A3. Chemical vapor deposition processes, B1. Silicon Carbide, B3. MEMS devices

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