Preliminary Studies of HTS Far-Infrared Micro-Bolometers

Abstract

We are developing an antenna coupled micro-bolometer using high temperature superconductors (HTS) for detection in the far infrared. A prototype consisting of a thin-film strip of Y₁Ba₂Cu₃O_x on MgO, coupled to a logarithmic periodic silver antenna has been fabricated. The measured responsivity was 10 V/W, giving an NEP of 8 · 10⁻¹⁰ W/Hz ^1/2 at 500 Hz. Measurements of the DC responsivity indicate that the intrinsic responsivity is larger, pointing to a poor coupling efficiency of the antenna. Excess noise is found to be proportional to the bolometer resistance at a fixed bias current. Currently we investigate the possi-bility of using self-supporting bufferlayers for high sensitivity microbolometers on silicon. Some success with Y₁Ba₂Cu₃O_x on silicon with an YSZ bufferlayer has been achieved.