Failure analysis of noise characteristics in GaAs MESFETs with parametric modeling approach

The noise degradation of GaAs MESFETs was investigated by thermal step stress tests with no bias in atmosphere. Minimum noise figure, associated gain, scattering parameters, and C-V profiles were measured during the tests. The noise degradation is mainly attributed to the decrease of AC transconductance, resulting from the carrier compensation by Ga vacancies in the channel. The decrease of effective carrier concentration resulting from the thermally activated interdiffusion between the gate metal and the GaAs channel layer is proposed to be the main failure mechanism for noise degradation of GaAs MESFETs.