The threshold voltage (Vth) of MOSFETs is primarily influenced by the source-to-bulk voltage (Vsb) rather than the drain-to-bulk voltage (Vdb) due to the device's operational characteristics. This dependence arises from the fact that the source is typically held at a constant potential, which stabilizes the channel formation. Additionally, after pinch-off, the drain is isolated from the channel charge by a depletion layer, further emphasizing the role of Vsb in determining Vth. This understanding is crucial for accurate MOSFET modeling and circuit design.
PREREQUISITESElectrical engineers, semiconductor physicists, and students studying MOSFET behavior and circuit design will benefit from this discussion.