Bias dependent etching of polysilicon mixed monocrystalline-polycrystalline silicon structures

An etching process developed for the realization of polysilicon structures using the standard CMOS process is described. Thin polysilicon beams have been fabricated using this technique. Electrochemical investigations give two important results: no anisotropic effects were observed and heavily doped polysilicon gives an OFP (oxide formation potential) of the same order as those of single-crystal silicon. A standard IC process flow and a PN junction etch-stop to suppress the clamping area step in order to realize a double-compensated structure was studied. These results demonstrate a new type of sacrificial layer that produces no damage to an SiO/sub 2/ layer. Poly-Si chemical properties in KOH aqueous solutions were also studied.<
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