Fabrication and characterization of niobium diffusion-cooled hot-electron bolometers on silicon nitride membranes

We have successfully fabricated niobium diffusion-cooled hot-electron bolometer (HEB) mixers on membranes of silicon nitride less than one micron thick. This advance has allowed us to construct a 1 /spl times/ 5 HEB receiver array intended for operation at 1.45 THz. This article provides an overview of the integration of the HEB array chip with silicon micromachined backshorts and feedhorns, discusses materials issues surrounding the device fabrication, reports resistance and I-V measurements, and compares HEBs fabricated on silicon nitride to similar devices on quartz substrates.