Microelectromechanical Systems I: Fundamentals of MEMS

This course explores the fundamental physical principles of Microelectromechanical Systems (MEMS) and their critical role in bridging the gap between the digital and physical worlds. Divided into five sections, it provides a foundational understanding of micro-scale physics, scaling laws, and the mechanical behavior of structures that enable modern sensing and actuation.The first section introduces the core definitions and scale of MEMS, distinguishing these integrated systems from traditional integrated circuits by their intentional mechanical motion. Students will explore a historical perspective starting with Feynman’s vision and gain an overview of ubiquitous applications, including inertial sensors, micromirrors, and microfluidics.The second section establishes the essential semiconductor basics required for MEMS engineering. Rather than focusing on complex circuit design, this module emphasizes the dual role of silicon as both an electrical and structural material. Topics include the physical intuition behind doping, the formation of PN junctions for electrical isolation, and why the MOSFET's capacitive nature makes it the ideal foundation for micro-scale sensing.The third section dives into the critical "Scaling Laws" that explain why the micro-world behaves so differently from our everyday experience. Students will analyze how geometric scaling causes surface forces, such as electrostatics and friction, to dominate over body forces like gravity and magnetism. This module highlights why electrostatic actuation is the industry workhorse and how small-scale structures achieve high resonant frequencies and rapid thermal response.The fourth and fifth sections focus on the mechanics and multiphysics of MEMS structures. Students will learn to model micro-beams and plates, accounting for the unique mechanical anisotropy of crystalline silicon. The course concludes with an analysis of electrostatic and thermal actuation, covering the fundamental "pull-in" instability limit and the impact of Joule heating on device reliability and design.By the end of this course, students will develop a strong physical intuition for the micro-scale, moving beyond standard electrical intuition to master the mechanical and thermal constraints of MEMS. Through conceptual modeling, they will gain the skills to analyze and design the next generation of smart, miniaturized systems.