Analysis of deep submicrometer bulk and fully depleted SOI nmosfet analog operation at cryogenic temperatures

Abstract

The increased demand for mixed mode digital-analog circuits is playing an important role nowadays. As the temperature of operation is decreased well-known improvements in the digital characteristics as reduction of the subthreshold slope and increased carrier mobility are obtained leading to better performance characteristics without scaling the dimensions. In this work, the impact of the temperature reduction on the analog characteristics of deep submicrometer bulk and fully depleted SOI nMOSFETs is compared. It is shown that the Early voltage does not vary appreciably with temperature and the intrinsic gain is substantially improved in bulk deep submicrometer transistors. On the other hand, deep submicrometer fully depleted SOI can operate at reduced bias current to bias the same load in base-band applications.