Sensitive high-T c transition edge bolometer on a micromachined silicon membrane

Abstract

Superconducting transition edge bolometers on micromachined silicon membranes have been fabricated. The optical response is 580 V/W at a time constant of 0.4 ms. The detectivity D* is 3.8×109 (cm Hz1/2 W−1) at a temperature of 84.5 K and within the frequency regime 100<f<300 Hz. This is one of the fastest composite type bolometers ever reported. Upon thermal optimization, this type of detector should be competitive with state-of-the-art quantum detectors.

Thermal budget calculations, design aspects, and device performance of high-Tc air-bridged microbolometers

“…This is approximately a factor of two higher than the experimentally determined value of 1250 V/W. 1 These values are approximately a factor of three higher than our own best responsivity value, reported for a composite type microbolometer, based on silicon membrane technology [8]. The difference between the calculated value and the experiment is very likely related to an uncertain optical absorption coefficient .…”

“…No further attempts have been made in this work to theoretically determine the noise equivalent power (NEP) or detectivity . The noise behavior of these devices is largely related to the structural quality of the superconducting films [7], [8] and, thus, is very difficult to model quantitatively.…”

A High-Tc Superconductor Bolometer for Remote Sensing of Atmospheric OH

“…The measured absorption efficiency q of the silicon membrane bolometer in the infrared is only 0.13 at h=13 ym and 0.16 at h=6 pm [3]. At 85 pm an absorptance around 10 % has been predicted [14].…”

“…A calculation of the detector NEP of the Si,N, membrane bolometer (with typical parameters T,=80 K, R=5 kP, a=l K-I [3], and G and T as listed in Table 2) shows that the most fundamental and important contributions to the detector noise are the phonon noise (i.e. the noise related to the thermal conductance G), and the excess noise in the high-T, film.…”

“…Recently we reported on high-T, GdBa2Cu,0,, transition edge bolometers on micromachined silicon membranes with an operating temperature of about 85 K [3]. For the fabrication an epitaxial YSZ+Ce02 buffer layer and an inhibition patterning technique were used.…”