Anomalous variability of subthreshold characteristics in bulk and silicon on insulator MOSFETs at cryogenic temperatures

Abstract The variability of subthreshold characteristics in bulk and fully depleted silicon on insulator (FDSOI) MOSFETs fabricated using 65 nm CMOS technology was measured at 1.5 K and 300 K using addressable transistor arrays. Measurements were conducted at a nominal temperature of 1.5 K, which is the lowest achievable set temperature of our cryogenic measurement system, in order to minimize thermal contributions. While the variability in FDSOI is smaller than that in bulk, anomalous subthreshold variability was observed in both bulk and FDSOI at 1.5 K. Similar anomalous subthreshold variability at 1.5 K, as previously reported, was confirmed for two different technologies, suggesting the existence of a common mechanism independent of process technologies.