Basics of Field Effect Transistors and Technology Scaling

This online course is the later part of the Principle of Semiconductor Devices Professional Certificate Program.

MOSFET as the most important component in integrated circuits will be introduced in this course. We will explain the basic operating principle of MOS capacitor and its application in charge-coupled devices (CCD) and CMOS Active Pixel Sensor (APS) in modern digital cameras.

Based on the MOS capacitor theory, different MOSFET operation regions, including strong inversion, subthreshold region, linear region, and saturation region, will be described. The deficiency of classical MOSFET theory and the need for more advanced mobility degradation and carrier velocity saturation theory will be elaborated.

To bridge the knowledge of transistors with practical applications, we will explain Moore’s Law and the approach to transistor scaling. Some specific features in modern MOSFETs including silicide, strain engineering, shallow junction, high-k gate dielectrics, metal gate stack, and their fabrication processes will be explained. The operating principle of advanced MOSFET structures, such as FinFET, nanowire transistors, gate-all-around MOSFET and 2D transistors, will also be introduced.

Week 1: MOS capacitor charges and capacitances
Introduction to the MOS capacitor structures, its charge and capacitance characteristics

Week 2: Charge coupled device, CMOS active-pixel sensor and MOS capacitor with a source
The operation principle of charge coupled devices, CMOS active pixel sensor for digital camera applications. The effect of adding a source to the MOS capacitor.

Week 3: Classical MOSFET I-V characteristics
Derivation of the classical MOSFET equations and the subthreshold characteristics.

Week 4: Mobility degradation and carrier velocity saturation
Correction to the classical pinchoff model by including the effect of mobility degradation and carrier velocity saturation.

Week 5: CMOS device scaling and short channel MOSFET
The effect of transistor scaling, short channel effects and the problems of small transistor design.

Week 6: Non-traditional nano-CMOS transistors
Introduction to the state-of-the-art transistors structure including SOI technology, FinFET, multi-gate MOSFET, tunnelling transistor and transistors based on 2-D materials.

Week 7: Final Exam