Understanding CMOS Technology Through TAMTAMS Web

Abstract

In the last decades, the CMOS technology has undergone an extraordinary evolution. Because of the continuous scaling process, CMOS transistors are now so small that millions can be easily fitted in a single chip. Shrinking transistor sizes have complex consequences on the performance of both the transistor itself and the system that is based upon it. Understanding and teaching the CMOS scaling process and its consequences on circuits are an increasingly difficult task. Furthermore, the scaling process is reaching an end, due to the continuously growing fabrication costs and the unavoidable physical limits on the smallest size achievable. As a consequence, many emerging technologies, such as carbon nanotubes and nanowires, are being studied as possible CMOS substitutes. Describing and teaching these new technologies, alongside the scaled transistor itself, adopting a complete and well-organized approach is a process that presents further difficulties. To solve these problems, we have started in the past years the development of TAMTAMS, a tool conceived to analyze CMOS circuits, from device to system level. The tool is based on models derived from the literature or, in some cases, internally developed and verified. It allows to analyze the main characteristics of a CMOS transistor, such as currents, threshold voltage, or mobility, considering different technology nodes and parameters, and to understand how they influence the circuits performance. The tool structure is open and modular, allowing, therefore, easy integration of further CMOS technologies and to compare them. In this paper, we present a total overview of the original tool, TAMTAMS Web. While the general concept behind the tool is still the same, the tool was completely rewritten around a Web interface. TAMTAMS Web is freely accessible to students and to any one interested in CMOS technology. As a future development, several post-CMOS technologies will be added to TAMTAMs Web, allowing, therefore, a comparison with the state-of-the-art CMOS. TAMTAMS Web is actively used in the Integrated System Technology (IST) held at the Politecnico di Torino. It defines a new way of learning, because students learn and understand the modern electronic technology both using TAMTAMS Web as an instrument, and being part of the development process, as part of the IST course.