A 512×512-element PtSi Schottky-barrier infrared image sensor

Abstract

An infrared image sensor with video quality has been developed for thermal imaging in the 3-5-/spl mu/m infrared band. The array size is 512/spl times/512. The device uses a platinum silicide (PtSi) Schottky-barrier photodetector. The charge sweep device architecture is applied to obtain a large fill factor. The pixel has a two-level polysilicon and two-level aluminum structure with a minimum design rule of 2 /spl mu/m. The pixel size and fill factor area 26/spl times/20 /spl mu/m/SUP 2/ and 39%, respectively. The responsivity has been improved by use of a thin metal film and an optical cavity structure. The barrier height is 0.22 eV, which corresponds to the cutoff wavelength of 5.6 /spl mu/m. The device operates at the standard TV frame rate. The noise at 300 K with f/1.5 optics is limited by the shot noise of the detector, and the device has the capability of resolving a 0.11 K temperature difference. High-quality infrared imagery has been obtained with a prototype infrared TV camera using this device.