TABLE OF CONTENTS The MOS transistor is obtained by adding one more terminal to the structure of Chap. 3, so that the inversion layer is contacted at two opposite ends. By applying a voltage between these ends, a current can be caused to flow in the layer. Since the density of carriers available for conduction depends on the gate potential, the latter can be used to either create or eliminate the inversion layer (i.e., turn the device "on" or "off") for digital applications or to modulate its conduction in a continuous manner for analog applications.
The path from the conception of the basic MOS transistor principle to the demonstration of working devices is spread over a quarter century [1] [2] [3] [4] see also Ref. [5]. The basic theory of MOS transistor operation was developed in the early nineteen-sixties. [6] [7] [8] [9] Extensive treatments on the MOS transistor were published in the late sixties, including investigations of the role of diffusion current and the role of substrate charge. [10] [11] [12] [13] [14] [15] [16] [17] [18] Our list of references to the work of the sixties is by no means complete, and many more references can be found in several early texts that helped spread the knowledge of the device. [11], [18] [19] [20] Starting in the sixties, the industry applied the newly acquired knowledge to the successful fabrication of digital ICs, and the need arose for efficient models for computer-aided design. [21]
