MOSFET Operation: Understanding NMOS Behavior

This lecture covers the operation of NMOS structures, focusing on the behavior of MOSFETs in various regimes. It begins with the basic structure of an NMOS transistor, explaining the roles of the source, gate, and drain. The instructor discusses the formation of the channel under the oxide layer and the significance of threshold voltage. The lecture then delves into the sub-threshold operation, comparing it to bipolar junction transistors (BJTs) and highlighting the conduction band dynamics. The discussion progresses to the linear and ohmic regimes, illustrating how gate voltage influences channel resistance and conductivity. The instructor explains the concept of channel pinch-off and saturation, detailing how these phenomena affect current flow. The lecture concludes with a summary of NMOS behavior in relation to drain voltage, emphasizing the transition from linear to saturation regions and the implications for current control. Overall, the lecture provides a comprehensive overview of NMOS operation, essential for understanding semiconductor devices.