Influence of bias heating on a titanium bolometer infrared sensor

A 128 by 128 pixel bolometer infrared focal plane array using thin film titanium has been developed. The device is a monolithically integrated structure with a titanium bolometer detector located over a CMOS circuit that reads out the bolometer's signals. Since the thermal conductance of the bolometer detector is minimized, the temperature of the detector itself is increased by applying the bias current. Under the present operating conditions of the titanium bolometer, this temperature increase becomes about 30 degrees Celsius. The influence of this bias heating on device destruction and degradation was experimentally investigated and is discussed. The noise equivalent temperature difference obtained with the device is 0.07 degrees Celsius. Since the fabrication process is silicon-process compatible, costs can be kept low.