An 8x8 thermopile based uncooled infrared sensor

International audience

We report the design, fabrication and measurement of a 8x8 thermophile based uncooled infrared sensor. The device is made with a CMOS compatible bulk micromachining process and integrates a matrix of infrared sensitive devices with standard scanning electronics. Pixels are made of a suspended plate connected to the substrate by four isolation arms containing several polysilicon/aluminium serially connected thermocouples. A part of the incoming infrared flux will be absorbed by the passivation silicon nitride layer of the suspended plate. One absorbed, the infrared flux induces a temperature rise in the plate. This temperature rise is measured by the thermocouples through the Seebeck effect. This paper presents the design and fabrication of the imager and the measurement with the help of a specific structure of the Seebeck coefficient of the thermocouples.