2014/10/09 by John Mark Kreikebaum, Blas Cabrera, Kreikebaum, John Mark +11
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Particle Detector Development and Performance #Superconducting and THz Device Technology
paper · pdf · doi:10.48550/arxiv.1410.2611
openalex publication_date 2014/10/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report on thin-film processing improvements in the fabrication of\nsuperconducting quasiparticle-trap-assisted electrothermal-feedback\ntransition-edge sensors (QETs) used in the design of Cryogenic Dark Matter\nSearch (CDMS) detectors. The work was performed as part of a detector upgrade\nproject that included optimization of a new confocal sputtering system and\ndevelopment of etch recipes compatible with patterning 40 nm-thick, mixed-phase\nW films deposited on 300-600 nm-thick, patterned Al. We found that our standard\nexothermic Al wet etch recipes provided inadequate W/Al interfaces and led to\npoor device performance. We developed a modified Al wet-etch recipe that\neffectively mitigates geometrical step-coverage limitations while maintaining\nour existing device design. Data presented here include SEM and FIB images of\nfilms and device interfaces obtained with the new Al etch method. We also\nintroduce a method for quantitatively measuring the energy collection\nefficiency through these interfaces.\n