Differential magnetoresistance technique for mobility extraction in ultra-short channel FDSOI transistors

Abstract

Ultra-thin Silicon-on-Insulator (SOI) transistor has proved to offer advantages over bulk MOSFETs for high-speed, low power applications. However, there is still a strong need to obtain an accurate understanding of carrier transport and mobility behaviour in these advanced devices. In this work, magnetoresistance technique is used to perform mobility measurements in Fully-Depleted Silicon-on-Insulator (FDSOI) MOSFETs. This technique has the advantage of allowing channel mobility measurement from weak to strong inversion without requiring the knowledge of the transistor’s effective channel length. The influence of different scattering mechanisms in the channel is investigated in details by obtaining mobility values at low temperatures. A new differential method enabling mobility extraction from pure channel magnetoresistance corrected for source–drain series resistance is presented. After the correction, in devices with large series resistance an increase in the extracted mobility is obtained in strong inversion, where the channel resistance is small and conventional mobility extraction is most affected by the impact of series resistance.