Micromachined silicon bolometers as detectors of soft X-ray, ultraviolet, visible and infrared radiation

This paper presents the development of micromachined thin-film silicon microbolometers which can be used for detection of soft X-ray, UV, visible and infrared radiation. The detector structure is a 1 μm thick polysilicon/Si₃N₄ membrane suspended over a cavity. This structure has been obtained by anisotropic etching of silicon with a previously deposited polysilicon/Si₃N₄ sandwich. Alternatively, porous silicon has been used as the sacrificial layer. Devices have been characterized. Good values of the voltage responsivity and detectivity have been obtained.