Enhanced Radiation Hardness in SOI MOSFET with Embedded Tunnel Diode Layer

Abstract

This paper presents an improved body tie structure for partially depleted silicon-on-insulator (SOI) MOSFETs. Inspired by tunneling current of degenerated p-n-junction at low forward bias, a tunnel diode layer is inserted at back channel forming a new type of body tie. The tunnel diode layer can be prepared either by ion implantation or in situ silicon deposition, which is fully compatible with present commercial SOI processes. The introduced body contact serves as an additional current flowing path for accumulated majority carriers generated by impact ionization or heavy-ion radiation, reducing critical floating body effects. The heavily doped tunnel diode layer extending from source to drain improves total dose radiation hardness and suppresses front-back channel coupling of SOI MOSFET for increasing back-gate threshold voltage and reduced width of space charge region. Experimental and simulation results validate the usefulness of the introduced body tie in enhancing radiation hardness of SOI transistor comparing with the conventional floating body devices. Therefore, SOI device with embedded tunnel diode layer can be considered as a promising candidate in spaceborne applications.