Search

Linear arrays of 40 X 40 micrometers 2 to 60 X 60 micrometers 2 microbolometers utilizing a semiconducting YBaCuO thin film as the IR sensitive material were fabricated and tested. This material displays a high temperature coefficient of resistance at room temperature, which makes it very attractive as an uncooled IR detector. The compatibility of semiconducting YBaCuO with Si micromachining techniques and CMOS technology and its ease of fabrication into thin films is attractive to the fabrication of inexpensive, high performance infrared detectors and imaging arrays. The room temperature responsivity, Rv, of the detectors was measured using 100 Hz chopped broad band infrared radiation to be as high as 104 V/W at 0.8 (mu) A current bias, providing a detectivity of 107 cm Hz1/2/W. The thermal conductance, G, of the isolation structure was measured to be a relatively high 10-5 W/K which limited the responsivity of the detector. Since Rv varies as 1/G, the responsivity and hence detectivity may be increased by up to two orders of magnitude by improving the thermal isolation. Zero bias responsivity was also observed on the structures, which was interpreted as pyroelectric IR detection. This was confirmed with independent pyroelectric current measurements.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Semiconducting YBaCuO thin films are a candidate for infrared bolometers operating at room temperature without the need for temperature control. Semiconducting YBaCuO thin films were fabricated by rf magnetron sputtering onto silicon substrates at room temperature. Room temperature deposition provides compatibility with CMOS technology to allow for the fabrication of low cost infrared imaging arrays with focal plane signal processing. The temperature coefficient of resistance (TCR) of the thin films was measured to be as high as 4% K-1 over a wide temperature range near 300 K. In this respect, amorphous YBaCuO thin films provided a higher TCR than epitaxial, tetragonal YBa2Cu3O6+x films. The noise voltage at 30 Hz was measured to be typically less than 1 (mu) V/Hz1/2. If the thin films are integrated into a typical air-gap thermal isolation structure, the projected responsivity Rv would be as high as 3.8 multiplied by 105 V/W with 1 (mu) A of current bias providing an estimated detectivity D* of 1.6 multiplied by 109 cm Hz1/2/W at a frame frequency of 30 Hz.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.