Magnetoresistance mobility extraction in the saturation regime of short channel MOS devices

The effect of magnetic field in the saturation regime of sub μm MOSFETs is being reported here for the first time. The study was based on bulk MOSFETs featuring a high-κ/metal gate with an equivalent oxide thickness of 2.4 nm. Channel length ranged from 1 μm down to 50 nm, while width was kept constant at 10 μm. It is found that it is possible to extract a magnetoresistance mobility μMR even in the saturation regime of operation and in turn study the observed μMR against channel length, temperature, drain voltage and gate voltage. For these sub-micron devices, electron transport is influenced by the high electric field that exists in the channel and velocity saturation, velocity overshoot and even quasi-ballistic effects could play a role for the shortest channel lengths Here, the observed μMR behavior is well interpreted using velocity saturation and overshoot effects.