Total ionizing dose effects on deca-nanometer fully depleted SOI devices

Total ionizing dose effects are investigated for the first time in deca-nanometer fully depleted (FD) silicon-on-insulator (SOI) devices. Charge trapping and the influence of device architecture are investigated in transistors with and without external body contacts. A radiation-induced high current regime is measured in floating body devices, both at high and low drain voltages. The mechanism responsible for the onset of this high current regime is investigated by 2D numerical simulations, and shown to result from the combined effect of short gate length and floating body potential in the intrinsic Si film. Transistors with a doped Si film are less sensitive to the high current regime. The use of external body contact in the device architecture completely stops the onset of high current regime, whatever the device gate length.

I. Introduction

The response of silicon-on-insulator (SOI) devices to total dose irradiation is more complex than for bulk silicon devices. The buried oxide, a unique feature of SOI technology, introduces an additional parasitic structure that must be taken into account. The total dose response of fully depleted (FD) transistors is even more complex because of the electrical coupling effect between front and back gate transistors [1]–[3] through the depleted silicon film. On top of all the previously mentioned parasitic structures, complex mechanisms can be triggered by radiation-induced charge trapping in the buried oxide, such as a total dose latch phenomenon, triggered by floating body effects [4]–[7].