Microelectronics Devices & Technology

Overview

MOS transistors. Background MOS capacitor theory, including derivation of threshold voltage. Influence of metal work function difference and oxide charge. MOS transistor structure. Linear and saturation regions of operation. Derivation of MOS transistor equations. Numerical modelling, including transconductance. Self-aligned structures. Threshold voltage control. MOS transistor scaling. Introduction to short-channel effects. Threshold voltage control for short channels. Mid-gap metals and high-κ dielectrics.

Overview of bipolar and MOS transistor fabrication. (a) Thermal oxidation of silicon. Deal-Grove model, including linear and parabolic growth approximations. Influence of process parameters on oxidation rates. Oxidation equipment and procedures. Oxide thickness measurement techniques. Selective oxidation. (b) Dopant diffusion in silicon. Theory of constant-source and limited-source diffusion. Diffusion coefficients and numerical modelling of dopant profiles. Diffusion equipment and techniques. Dopant profile determination, including sheet resistance measurements. (c) Ion implantation of dopants in silicon. Numerical modelling of dopant profiles, including junction depth. Selective ion implantation. Implantation damage and channelling. Modelling of dopant profiles after thermal annealing. Buried insulators by ion implantation.

Bipolar transistors. Origin of internal current components, including recombination currents. Definition of current gain, emitter efficiency and base transport factor. Background diode theory, including minority carrier concentration profiles. Calculation of internal current components and current gain. Non-uniform base profiles. Calculation of base transit time and cut-off frequency. Modelling of base spreading resistance. Current crowding. Bipolar transistor scaling. Self-aligned structures. Heterojunction bipolar transistor theory and Si-based HBT fabrication techniques.

Coursework:
1. MOS transistor homework
2. Microelectronics technology homework
3. Bipolar transistor homework

Learning Objectives

• Comprehensive teaching of natural science and engineering aspects of microelectronics and application to the solution of complex problems.
• Analysis of complex problems using first principles of natural science and engineering aspects of microelectronics
• Application of appropriate analytical techniques to model complex problems
• Selection and application of appropriate semiconductor and associated materials and microfabrication processes

Skills

Assimilation of lecture material. Application to microelectronics device design and fabrication process design

Assessment

None