chapter  9
8 Pages

- How Big Is an Electron

In this last chapter, I want to describe a thread that began just under two decades ago. At the same time, the reader may wonder why I put so much effort into the last chapter with regard to the manner of understanding quantum mechanics. The importance of this lies in the thread to be discussed here, which connects us back to the very small transistors that have arisen as Moore’ law has continued to progress. Today, we utilize individual transistors in our chips that may be described as nanoscale devices. Critical lengths in these devices are at the 20 nm (or smaller) scale. But in these devices we expect that certain quantum effects will dominate the transport, and therefore the performance of the devices. In these small structures, one must begin to worry about the effective size of the electrons (or holes) themselves. Of course, there are many estimates about the effective size, most of which would preclude having even a single electron in some of the devices being made today. Certainly, the effective size is going to be larger than the very small estimate from classical physics. Moreover, how can we connect the larger size with the apparent classical behavior of the devices.