Design and post-process of an integrated CMOS-MEMS IR emitter with an embedded detector

This paper presents the design and post-process of a CMOS-MEMS IR emitter device implemented in standard AMS 0.35μm CMOS process. The IR emitter is based on thermal heating of a chain of tungsten vias implemented on the Back-End-Of-Line. This heating element is protected from oxidation with a SiO 2 film and is thermally isolated from the substrate. The IR light emitted from the heating element is directed through a waveguide made of SiO 2 and air, used as core and cladding layers, respectively. The optical waveguide is connected to a photodiode used as detector, implemented in the Front-End-Of-Line. The post-process used to isolate the thermal emitter and create the waveguide was done through a maskless post-process that selectively etched the SiO 2 layers and used the aluminum film as a sacrificial material. The release of both emitter and optical waveguide was confirmed by visual inspection using optical and electronic microscopes.