MOSFET Basics: NMOS and PMOS Characteristics

This lecture covers the fundamental principles of MOSFET operation, focusing on NMOS and PMOS transistors. It begins with a review of NMOS functioning in strong inversion, detailing the formation of the channel and the distribution of charge along it. The instructor introduces a simplified model to derive equations for drain current, emphasizing the relationship between charge, mobility, and electric field. The discussion progresses to the saturation regime, explaining how the channel pinches off and the implications for current flow. The effects of channel length modulation are also examined, highlighting how variations in channel length influence drain current. The lecture concludes with a comparison of NMOS and PMOS transistors, noting differences in their operation and characteristics, particularly regarding threshold voltage and mobility. This comprehensive overview provides a solid foundation for understanding MOSFET behavior in electronic circuits.