Chapter 2
Physical and Technological Limits of Classical Electronics
‘Science may set limits to knowledge, but should not set limits to imagination’
Bertrand Russell
2.1 Introduction
Progress in the performance of electronic devices was for a long time well described by the empirical Moore's law [1]. It states that the economically justified number of transistors in a microchip grows exponentially in time. In the first formulation of 1965 it was postulated, that this figure doubles every 12 months, while now (2010) it has been scaled to approximately 24 months. Moore's law cannot be, however, valid forever. The development of information processing technologies (and hence the ultimate performance of the resulting devices) is limited by several factors. Some of the constrains are simply a result of fundamental principles, including the granular structure of matter, Einstein's special theory of relativity, Heisenberg's uncertainty principle and others. These limits are absolute in the sense that they impose constraints on any physical system and cannot be eliminated by technological progress. The only way to ignore these constraints may consist in changing the information processing paradigms and utilizing the apparent hindrances. For example, quantum phenomena (which are deleterious for classical electronic devices) can be utilized in quantum computing.
Another kind of limitation results from applied technologies and economics. Device cooling, doping inhomogeneity, crosstalk, ...
