Variability of DRAM Peripheral Transistor at Liquid Nitrogen Temperature

Dynamic random-access memory (DRAM) peripheral nMOSFETs with various channel length and channel doping concentration are analyzed at liquid nitrogen temperature (LNT). Important device parameters in circuit designs such as subthreshold mismatch, subthreshold swing (SS), transconductance, and drain-induced barrier lowering (DIBL) are analyzed at temperatures ranging from room temperature to LNT. In devices with relatively low channel doping, exacerbation of threshold mismatch at cryogenic temperatures is alleviated. Devices with lower doping exhibit better SS and transconductance characteristics. DIBL improved in short-channel devices at cryogenic temperatures, and the degradation of the DIBL with low doping is relatively small.