Influence of the gate leakage current on the noise performance of MESFETs and MODFETs

The influence of the gate leakage current (GLC) on the noise performance of MESFETs (metal-semiconductor field effect transistors) and MODFETs (modulation-doped field effect transistors) is investigated. It is shown that the noise performance of FETs is strongly dependent on the GLC value, especially at a few gigahertz. This effect has to be taken into account in the CAD (computer-aided design) of ICs. For high GLC devices, the degradation of the noise performance can be observed even in the millimeter wave range. The theoretical results are discussed and are compared with experimental data.<>