Epitaxial YBa2Cu3O7 superconducting infrared microbolometers on silicon

Superconducting transition-edge infrared microbolometers have been fabricated by silicon micromachining using an epitaxial YLa.05Ba1.95Cu3O7-x (YBCO) film on a epitaxial yttria-stabilized zirconia buffer layer on silicon. The low thermal conductance of the micromachined structures combined with the sharp resistance change at the superconducting transition results in very sensitive infrared detectors. The broadband response of these thermal detectors makes them particularly useful at wavelengths longer than the typical operating range of semiconductor detectors ((lambda) greater than about 20 micrometers ) at moderately high temperatures (T approximately 70 K and higher). The use of standard silicon processing promises low-cost monolithic integration of the readout electronics for arrays of these devices. Preliminary measurements are reported here on a device 140 micrometers X 105 micrometers in size with a detectivity, D*, of 8 +/- 2 X 109 cm Hz1/2/Watt, and NEP of 1.5 X 10-12 Watts/Hz1/2 at 2 Hz and 80.7 K. This value of D* exceeds the highest previously reported D* for a YBCO transition-edge bolometer, and is comparable to the highest reported D* for a thermal detector operating at greater than about 70 K. The thermal time constant for this device was 105 +/- 20 msec.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.