High-performance linear arrays of YBa2Cu3O7 superconducting infrared microbolometers on silicon

Single detectors and linear arrays of microbolometers utilizing the superconducting transition edge of YBa 2 Cu 3 O 7 have been fabricated by micromachining on silicon wafers. A D* of 8 +/- 2 X 10 9 cm Hz 1/2 /watt has been measured on a single detector. This is the highest D* reported on any superconducting microbolometer operating at temperatures higher than about 70 K. The NEP of this device was 1.5 X 10 -12 watts/Hz HLF at 2 Hz, at a temperature of 80.7 K. The thermal time constant was 105 msec, and the detector area was 140 micrometers X 105 micrometers . The use of batch silicon processing makes fabrication of linear arrays of these detectors relatively straightforward. The measured responsivity of detectors in one such array varied by less than 20% over the 6 mm length of the 64-element linear array. This measurement shows that good uniformity can be achieved at a single operating temperature in a superconductor microbolometer array, even when the superconducting resistive transition is a sharp function of temperature. The thermal detection mechanism of these devices gives them broadband response. This makes them especially useful at long wavelengths (e.g. (lambda) > 20 micrometers ), where they provide very high sensitivity at relatively high operating temperatures.