Improvement of a nano-scale silicon on insulator field effect transistor performance using electrode, doping and buried oxide engineering

Document Type: Research Paper

Authors

1 Department of Electrical and Computer Engineering

2 Institute of nanoscience and nanotechnology, University of Kashan

3 Technical and Vocational University, Kashan

4 Electronics and Nanoscale Engineering Research Division, School of Engineering, University of Glasgow, Glasgow, UK

Abstract

In this work, a novel Silicon on Insulator (SOI) MOSFET is proposed and investigated. The drain and source electrode structures are optimized to enhance ON-current while global device temperature and hot carrier injection in the gate electrode are decreased. In addition, to create an effective heat passage from channel to outside of the device, a silicon region has embedded in the buried oxide. In order to reduce the device leakage current and controlling the threshold voltage, a p-type retrograde doping is introduced into channel region. Since the air has the least permittivity among materials, it can be utilized to decrease the device parasitic capacitances. Based on this, an air gap is embedded in the buried oxide near the silicon to improve RF performance of the device. Because the source and drain are embedded in and over the silicon film in the source and drain regions, we called this structure EEIOS-SOI. “EEIOS” stands for “Embedded Electrodes In and Over the Silicon film”. During this work, EEIOS-SOI MOSFET is compared with a conventional SOI MOSFET and another SOI MOSFET with just Embedded Electrodes In the Silicon Film (EEIS-SOI). EEIS-SOI presents better electrical figure of merits including lower subthreshold slope and lower leakage current in simulations. An immense investigation among these devices shows that EEIOS-SOI MOSFET has better transconductance, lower gate injection leakage current and lower temperature related to DC parameters and higher cut off frequency, gain bandwidth product and unilateral power gain related to AC figures of merits compared to its counterparts.

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