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 alum inium metallisation on a double side polished silicon wafer is used for fab rication of the multi-slit gratings. The dispersed spectrum propagates thro ugh this silicon wafer and is projected on an array of polysilicon thermopi les, integrated in a second bulk micromachined silicon wafer. The two wafer s are bonded at low temperature. An IR spectrometer results, which is simpl e to fabricated and remains compatible with standard IC processing. (C) 200 1 Elsevier Science B.V. All rights reserved.