Fabrication of Ultrasensitive TES Bolometric Detectors for HIRMES

The high-resolution mid-infrared spectrometer (HIRMES) is a high resolving power (R ~ 100,000) instrument operating in the 25–122 μm spectral range and will fly on board the Stratospheric Observatory for Far-Infrared Astronomy in 2019. Central to HIRMES are its two transition edge sensor (TES) bolometric cameras, an 8 × 16 detector high-resolution array and a 64 × 16 detector low-resolution array. Both types of detectors consist of Mo/Au TES fabricated on leg-isolated Si membranes. Whereas the high-resolution detectors, with a noise equivalent power (NEP) ~ 1.5 × 10−18 W/rt (Hz), are fabricated on 0.45 μm Si substrates, the low-resolution detectors, with NEP ~ 1.0 × 10−17 W/rt (Hz), are fabricated on 1.40 μm Si. Here, we discuss the similarities and differences in the fabrication methodologies used to realize the two types of detectors.