Temperature dependence of substrate current in silicon CMOS devices

The temperature dependence of the substrate current in CMOS devices is investigated over the range 20-300 K. It is shown that the simple classical substrate current law is applicable down to near-liquid helium temperature for both n and p channel devices. The exponent factor B of the substrate current law is found to be almost independent of temperature. Moreover, the increase of the substrate current at low temperature is attributed to the temperature variation of the pre-exponent coefficient A of the substrate current law. The modelling of the substrate current as a function of gate and drain voltages is therefore achievable over a wide temperature range provided an accurate drain current model is employed.