| The goal of this book is twofold. First, it explains the principles and physical mechanisms of Floating Gate device operations. Second, starting from a general overview on Compact Modeling issues, it illustrates features and details of a complete Compact Model of a Floating Gate device, the building block of Flash Memories, one of the “hottest” products in the semiconductor industry.
Flash Memories are one of the most innovative and complex types of high-tech, nonvolatile memories in use today [see, for example, Proceedings of the IEEE, Special Issue on: Flash Memory Technology, April 2003]. Since their introduction in the early 1990s, these products have experienced a continuous evolution from the simple first products to emulate EPROM memories, to the extreme flexibility of design application in today products. This is an enabling technology: future limits are beyond our current expectations and limited only by our imagination.
Flash are not just memories, they are “complex systems on silicon”: they are challenging to design, because a wide range of knowledge in electronics is required (both digital and analog), and they are difficult to manufacture. Physics, chemistry, and other fields must be integrated; and conditions must be carefully monitored and controlled in the manufacturing process.
This book gives our personal vision on Compact Modeling of Floating Gate Devices. It collects the results of our research activity in these last years, some of which have already been published, after peer review process, in international journals.
The philosophy we have adopted to develop the Compact Model of Floating Gate devices proposed in this book is based on a modular approach. The Floating Gate device is depicted as a simple subcircuit where device operations and functionality are simulated by specific current generators, each one describing through compact formula the current induced by the single physical phenomenon. This modular approach allows different levels of accuracy and complexity of the model, and leaves the door open for any improvement and change to tailor the model to new and different technologies.
In this book, the specific example of the Compact Model of a Floating Gate device is illustrated. Besides this specific content dedicated to Non-Volatile Memory people, we believe that the modular philosophy followed here could be a successful strategy for compact modeling, exported also to other devices. We hope that our personal vision of Compact Modeling can be shared by many in different areas of Semiconductor Industry, where compact modeling is important. |
