Some CMOS device constraints at low temperatures

Two of the CMOS device constraints at low temperatures have been identified, namely, the transconductance and the breakdown voltage roll-off. In the short channel devices, the transconductance first increases then decreases with the decreasing temperature. This transconductance roll-off phenomenon is likely caused by the parasitic series resistance in the source and drain regions. The breakdown voltage of the MOSFET´s due to the parasitic bipolar transistor action decreases with the decreasing temperature, which is caused by the increase of the impact ionization rate at low temperatures.