Fabrication of MKIDS for the MicroSpec Spectrometer

• Published in: IEEE transactions on applied superconductivity Vol. 23; no. 3; p. 2400404
• Main Authors: Patel, A., Brown, A., Hsieh, W., Stevenson, T., Moseley, S. H., U-yen, K., Ehsan, N., Barrentine, E., Manos, G., Wollack, E. J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Circuit properties; Construction; Detectors; Dielectrics; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronics; Exact sciences and technology; Fabrication; Magnetic devices; Microstrip; Microstrip devices; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; microwave kinetic inductance detector (MKID); Molybdenum; molybdenum nitride; Niobium; Oscillators, resonators, synthetizers; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductors; Silicon; spectrometer; Spectrometers; Substrates; Superconductors; Transformers and inductors; wafer bonding; Wavelengths; Resolving power; State of the art; Roughness; Microstrip devices; spectrometer; microwave kinetic inductance detector (MKID); Instrumentation; Inductor; Optimization; Wafer bonding; Inductance; Superconducting materials; Microelectronic fabrication; Wide band; niobium; Wafer; Low temperature; Resonator; Patterning; molybdenum nitride; Microwave detectors; Measurement sensor; Cryogenic temperature; Crystalline material; High power
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2013.2240152

Microspec is a new class of submillimeter and millimeter (250-700 μm wavelength) spectrometer, in which the wavelength separation and detection of incident light is done on a single substrate. The instrument is designed for space exploration by offering high spectral resolving power over a broad band, while being orders of magnitude smaller in mass and volume than the present state-of-the-art. The key enabling components for Microspec are background-limited microwave kinetic inductance detectors, which operate over the full bandwidth of the spectrometer. Here we present our fabrication strategy for making these sensitive detectors. A microstrip architecture utilizing a 0.45-μm crystalline silicon dielectric with a molybdenum nitride kinetic inductor material has been adopted. We have optimized wafer-scale lithographic patterning, and have developed processes that allow us to minimize surface roughness that may contribute to detector noise. Additionally, we have optimized the low-temperature wafer bonding process; this process allows us to build superconductors on both sides of the silicon dielectric layer. We present a final fabricated device and resonator operation at cryogenic temperatures.