Substrate and device pattern dependence of the thermal crosstalk in y Ba 2Cu 3O 7-δ transition edge bolometer arrays

摘要

Using YBa 2Cu 3O 7-δ (YBCO) thin films, pulsed laser deposited on 1-mm-thick LaAlO 3 or SrTiO 3 substrates, we made 4 × 1 pixel arrays of transition edge bolometers with separations between neighboring pixels ranging from 40 μm to 170 μm for testing purposes. We investigated the effects of the YBCO film thickness (200 and 400 nm), substrate material, and back-etching of the substrate, on the crosstalk between the pixels of the arrays. The investigation was based on the analysis of the voltage response of the dc current biased bolometers versus the modulation frequency of a near-infrared laser source. We observed that the bolometer arrays made of 400-nm-thick films had less interpixel thermal crosstalk than the 200-nm-thick films. The effect of substrate thickness on the response of the pixels was investigated by up to 500 μm back-etching of the substrates. The bolometers made on back-etched LaAlO 3 substrates had anomalous crosstalk response behavior, which was effective at higher modulation frequencies. In addition, we present an analytical thermal model for explaining the observed effects of the thermal crosstalk on the response characteristics of the pixels of the arrays. We report the measured response and the anticipated thermal crosstalk of the characterized bolometers'. We describe the responses based on the thermal models and discrepancies from the model's predictions. © 2006 IEEE.