COLLAPSE AND LARGE-SIGNAL MODELING OF GAAS FIELD-EFFECT TRANSISTORS AT 77-K

A complete electrical characterization of different types of GaAs fiel d effect transistors at liquid nitrogen temperature is performed. The trapping-detrapping mechanisms on deep levels are particularly adresse d and a method is proposed to circumvent the collapse phenomenom which otherwise limits the electrical performances. From these measurements a HEMT non-linear model is extracted and is found efficient for the p rediction of the large signal power out versus power in characteristic of a cooled HEMT. A further application could be the optimized design of a cooled low phase noise oscillator.