Distribution of 1/ƒ noise in an epitaxial GaAs MESFET

Abstract

A method was devised to determine the distribution of 1/ƒ noise generation in the conducting channel of a field-effect transistor. This newly devised method was applied to an epitaxial GaAs MESFET and the vertical distribution of 1/ƒ noise generation was determined. A noise current source, which represents noise generated in the conducting channel, was assigned to the conventional e n - i n representation, in which all the noises are represented by the equivalent noise voltage and current sources at the gate. The magnitude of each noise source was separately determined by measuring the dependence of noise output on the resistance in the gate circuit of the common source amplifier including the FET to be measured. Measurements were performed on a dual gate FET in the frequency range from 0.01 Hz to 25 kHz. It was shown that the more noise is generated in the portion next to the substrate than in the portion at the middle of the active layer.