Uncooled infrared focal plane array having 128 x 128 thermopile detector elements

A 128 X 128 element thermopile infrared image sensor has been developed. This device has a monolithically integrated structure to increase fill factor. The CCD for signal charge accumulation and signal charge read-out is fabricated on the silicon surface. Over the CCD, silicon dioxide diaphragms for thermal isolation are made by using micromachining technology. On each diaphragm, 32 pairs of p-type polysilicon and n-type polysilicon thermopile are formed. The noise equivalent temperature difference obtained by the device is 0.5 degree(s)C with an f/1 lens. Since the materials used are the same as those for silicon ICs, and since the whole fabrication process is carried out at the silicon IC plant, it can be said that a low cost uncooled infrared image sensor is realized by this technology.