Development of Large-active-area Superconducting Single-photon Detectors Using Photolithography

Superconducting single photon detector – is a breakthrough allowing to detect wide-range infrared radiation. Device has the highest quantum efficiency, count rates in the tens of MHz and very low dark counts. SSPD forms an ultrathin superconducting meandered strip 100-150 nm in width. There is a trend towards an increase of an active area and a width of detectors up to micrometers. Intensive scientific activity drives in a field of creation a single-photon camera. One of technological stages for SSPD fabrication is to form an active area topology with electron-beam lithography. Typical current value of the systems is millions US dollars that enhances a prime cost of the devices and restrains the commercial SSPD market. Master`s dissertation is devoted to development single-photon detectors with photolithography instead of electron-beam one. Technological route is defined, parameters of superconducting films, photoresist and exposure dose are optimized. Samples of different widths in the range from 950 to 2500 nm were created. Experimental research of critical current and quantum efficiency was carried out. Functionality and prospect of large-active-area SSPD developed using photolithography are proved. Along the data of the dissertation, parameters and topology of detectors are defined and a mask with different configurations were made as well. Further investigations of large-active-area SSPD are continued in doctoral school.