Niobium Titanium Nitride Thin Film Coating

摘要

Impedance matched coatings are used for absorber applications to couple mid-to far-infrared (IR) radiation to an ultrasensitive bolometric detector suspended on an ultrathin dielectric membrane. In order to provide adequate responsivity, the bolometric detector must have a low heat capacity. Furthermore, to achieve an optimal signal-to-noise ratio, spectral filtering of the incident radiation is desirable. Conventional approaches for absorber coatings are susceptible to aging, which hinders the transient optical efficiency of the instrument. Additionally, conventional absorber coatings have a high heat capacity that impacts the performance of low-background cryogenic detectors. Conventional absorber coatings also are reactive in the short wavelength limit, which correspondingly reduces their coupling efficiency. Furthermore, some thin film absorber coatings have extremely high intrinsic stress, which can cause the dielectric membranes to break or bend.