Novel Fabrication Technology for Thermoelectric Infrared Sensors Using Surface Micromachining

In this paper a novel fabrication technology for thermoelectric infrared sensors is presented. For the first time, the thermal insulation of the absorber structure is achieved by self-assembling multilayer thermocouples. After removal of a sacrificial oxide layer by vapor hydrogen fluoride (vHF) etching, the thermocouples lift off due to residual stress gradients. This provides the necessary distance between the absorber and the substrate. Compared to state-of-the-art sensors, this implementation does not require extensive bulk processing such as grinding and cavity etching to achieve a thermally isolated absorber structure. The deflection of the realized structures has shown high agreement with an analytical model which is also presented in this paper.