Analog Integrated Circuit Design, 2nd Edition

This chapter describes the steps and processes used in realizing modern integrated circuits with emphasis on CMOS processing. After processing is presented, circuit layout is covered. Layout is the design portion of integrated-circuit manufacturing, in which the geometry of circuit elements and wiring connections is defined. This process leads to the development of photographic masks used in manufacturing an integrated circuit. The concepts of design rules and their relationship to integrated circuits are emphasized. Next, circuit layout is related to the transistor models. Here, it is shown that once the layout is completed, the values of certain elements in the transistor models can be determined. This knowledge is necessary for accurate computer simulation of integrated circuits. It is also shown that, by using typical design rules, one can make reasonable assumptions to approximate transistor parasitic components before the layout has been done. Variability in device parameters is unavoidable and particularly problematic for analog circuits. These variations are modeled and their impact on analog circuits analyzed. Finally, analog layout issues are then discussed, including matching and noise considerations.

2.1 CMOS PROCESSING

In this section, the basic steps involved in processing a CMOS integrated circuit are presented. For illustrative purposes, we describe here an example ...