Infrared micro-spectrometer based on a diffraction grating

The optical properties of crystalline silicon in the IR spectral range have been used for the realisation of a grating type microspectrometer. An aluminium metallisation on a double side polished silicon wafer is used for fabrication of the multi-slit gratings. The dispersed spectrum propagates through this silicon wafer and is projected on an array of polysilicon thermopiles, integrated in a second bulk micromachined silicon wafer. The two wafers are bonded at low temperature. An IR spectrometer results, which is simple to fabricated and remains compatible with standard IC processing. (C) 2001 Elsevier Science B.V. All rights reserved.