3D Flash Memories

This book guides the reader through the§next step in the evolution of NAND flash memory technology, namely the§development of 3D flash memories, in which multiple layers of memory cells are§grown within the same piece of silicon. It describes their working§principles, device design and architectures, fabrication techniques and§practical implementation, and describes how 3D flash is a brand new technology,§not only because of its multi-layer architecture but also because it is based§on a new type of NAND memory cell.§§The book begins with two chapters§reviewing the principles of NAND flash memories and planar charge trap§technology, before chapter 3 introduces 3D chapter trap technology. 3D can be§combined with the other storage dimensions, namely multilevel and die stacking;§chapter 4 considers die-stacking approaches, their main topologies, designs and§integration issues, whilst chapter 5 reviews the principles, materials and cost§structure of 3D silicon monolithic systems. There is a wide range of§different materials and vertical architectures; each vendor has its unique§solution, and the book contains a series of chapters reviewing the most common approaches in the§industry. The book concludes with a§chapter on SSDs based on 3D NAND flash, considering performance, power and cost§issues.§§How many generations of 3D flash memory§are possible? Can 3D flash go down to feature sizes below 20nm? How many layers§can be integrated in the same silicon? Will 3D flash be reliable enough for§consumer and enterprise applications? These are some of the questions that this§book answers by providing insights into 3D flash memory design, process§technology and applications.§