High Yield Front-etched Structure for CMOS Compatible IR Detector

A front-etched structure for CMOS compatible IR detector is demonstrated and tested in this paper. Properly-arranged narrow windows in IR absorbing area are designed along the [100] direction on the (100) Si wafer. Experimental result shows that the design of the etching windows is characteristic of short release time and high IR sensitive area occupancy rate up to 50%. Based on CMOS compatible MEMS technology such as high precision mask, LPCVD, IBE dry etching, TMAH wet etching, a p-doped/ n-doped polycrystalline silicon thermopile is fabricated with such a structure It shows that the release time through TMAH silicon anisotropic etching is only 3 hours for an area of 500 mum times 500 mum with a yield better than 95%, which paves a way for researches of large scale IR array.