120 × 90 element thermoelectric infrared focal plane array with precisely patterned Au-black absorber

Abstract

This paper presents a 120 × 90 element thermoelectric infrared focal plane array with a precisely patterned Au-black absorber that provides high responsivity and a low cost potential. The device has a responsivity of 3900 V/W. The overall chip size is 14.4 mm × 11.0 mm with a 12.0 mm × 9.0 mm imaging area. Each detector consists of two pairs of p–n polysilicon thermocouples and has external dimensions of 100 μm × 100 μm and internal electrical resistance of 90 kΩ. The precisely patterned Au-black infrared absorbing layer was achieved by both a low-pressure vapor deposition technique and a lift-off technique utilizing a PSG sacrificial layer. These techniques make it possible to obtain a Au-black pattern with the same degree of accuracy as with the CMOS process. The Au-black layer showed high absorptance of more than 90% to the light source with a wavelength of from 8 to 13 μm. This performance is suitable for automotive applications as well as consumer electronics.