Theory and application of the field-effect transistor. Part 1: Theory and d.c. characteristics

The d.c. theory of the field-effect transistor is considered, and extensions of the theory are presented to account for the effects of a nonuniform channel impurity-density profile. It is shown that varying mobility effects could account for the observed Id/gm and gm variations with gate bias observed in certain silicon devices. A number of design formulas for abrupt and linearly graded junction devices are obtained and compared with experimental measurements. The effects of temperature on the device are considered in considerable detail and experimental results are compared with theory. It is shown that, provided that certain conditions are fulfilled, the device can be biased so as to operate with an almost zero temperature coefficient over a wide temperature range.