Threshold Voltages of Normally Off MESFET's

The threshold voltage of “normally off” Si-MESFET s for simple dc-coupled circuits is defined and computed with a two-dimensional device model, taking into account carrier velocity saturation and diffusion. The influence of the main parameters, gate length conducting-layer thickness, and doping is investigated outside, the range of Shockley's equations. A threshold voltage of a MESFED with a 1-μm gate length UT= 0.2 V ± 10 percent requires a conducting layer thickness tolerance d = 0.15 μm ± 3 percent. Copyright © 1972 by The Institute of Electrical and Electronics Engineers, Inc.