Arrays of un-cooled micro-bolometers based on amorphous silicon–germanium thin films deposited by plasma

We report the study of a fabrication process and characterization of one (1D) dimensional arrays of un-cooled micro-bolometers based on amorphous silicon–germanium thermo-sensing films deposited by a low frequency PECVD at low temperature and fully compatible with the IC fabrication technology. Two different thermo-sensing films have been employed in the micro-bolometer arrays, an intrinsic film a-SixGey:H and a boron alloy a-SixGeyBz:H. array is composed of 32 elements. The active area of the cells in the array is Ab = 70 × 66 μm2 and the area of the array including interconnection lines and pads is AA = 1.6 × 3.1 mm2. The temperature dependence of conductivity σ(T), current–voltage characteristics I(U) and spectral noise density have been measured in the micro-bolometer arrays with both types of thermo-sensing films in order to characterize and compare their performance characteristics, such as responsivity R and detectivity D∗.