Substrate current measurements in thin SOI MOSFET´s at 300 and 77 K

Measurements of impact-ionized hole current in fully depleted SOI (silicon-on-insulator) MOSFETs at room temperature and liquid nitrogen temperature are reported. The measured current exhibits properties similar to those of the substrate current in bulk transistors, except for higher drain biases when the parasitic bipolar in the device is significant. Since the body contact is effective in collecting only a small fraction of the total generated hole current, the body contact cannot be used to eliminate the bipolar action in thin SOI, at least for channel widths on the order of 10 μm