An anomalous hole mobility degradation effect at low temperature and low gate overdrive of a compensated p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET) is reported. Measurements are performed with great care, including the temperature calibration of the device and measurement timing control to exclude unwanted self-heating effect. Methods to determine threshold voltage and effective mobility are discussed. The anomalous effect can be explained by the trapping or freezing out of the electrons ionized from donor level at the acceptor site. The additional charged center enhances the Coulomb scattering of conducting holes that are transported in this region.
- Hole mobility
- Low-temperature characteristics