面向窄线宽超导纳米线单光子探测器的电子束曝光技术

超导纳米线单光子探测器是新型超导电子器件,因其具有高探测效率、低暗计数及低时间抖动等优势,在量子信息、激光雷达等方面已得到广泛的应用.目前主流超导纳米线单光子探测器主要工作在1.5μm以下的可见光和近红外波段.中红外波长的红外探测技术在基础科学、医学、日常生活以及军事等广泛领域发挥着重要作用,中红外单光子探测器可以使得中红外波段探测技术进入量子极限灵敏度.根据超导纳米线单光子探测器探测机理,超窄线宽的纳米线条可以提升超导纳米线单光子探测器在中红外波长的灵敏度.电子束曝光技术是目前实现超导纳米线单光子探测器纳米线线条加工的主流技术,电子束抗蚀剂种类繁多,面向超窄线宽超导纳米线单光子探测器器件的制备需求,对两款抗蚀剂进行性能测试表征,和窄纳米线制备尝试.根据负性电子束抗蚀剂MaN-2401在制备窄线宽时的显著优点,优化工艺,利用其成功制备出50 nm线宽超导纳米线单光子探测器并成功实现了2000 nm的单光子响应.

Electron-beam Lithography for Narrow Linewidth Superconducting Nanowire Single-Photon Detector

Superconducting nanowire single photon detector (SNSPD) is a novel superconducting electronic device, which has advantages of high detection efficiency, low dark count rate and low time jitter, SNSPD has been widely used in quantum information, lidar and other fields. At present, the mainstream SNSPD mainly works visible and near infrared band with the wavelengths below 1.5 Hm. The mid-infrared detection technology plays an important role in basic science, medicine, daily life, military and other fields. The mid-infrared single photon detector may provide the mid-infrared detection technology with quantum limit sensitivity. According to the detection mechanism of SNSPD, ultra-narrow nanowires can improve the sensitivity of SNSPD in mid-infrared wavelength. At present, electron-beam lithography is the key nano-fabrication technique for SNSPD, There are many kinds of electron beam resists. In order to meet the fabrication requirements of SNSPD devices with ultra-narrow linewidth, we tested and characterized two resists for producing ultra- narrow nanowires. With negative electron beam resist MaN-2401, we optimized the fabrication processes and successfully fabricated SNSPDs with 50 nm linewidth nanowire. The single photon response of 2000 nm wavelength was demonstrated successfully.