On the origin of low frequency noise in GaAs metal-semiconductor field-effect transistors

The origin of low frequency (LF) noise of GaAs metal-semiconductor field-ef fect transistors (MESFETs) was examined. A few generation-recombination com ponents dominate the flicker noise present in the measured spectral noise i ntensity. It follows that the noise scales proportionally to L-3 (L stands for channel length). The earlier is obeyed perfectly when the noise origina ted in the channel access areas is negligible compared to the LF noise of t he region underneath the gate. Next, it was observed that the corner freque ncy of the Lorentzian noise components depends on the gate-to-source bias a nd does not depend on the device geometry. The third important observation is that the LF noise power does not depend on the source-to-gate bias at fr equencies higher than 100 Hz. It was shown that both fluctuations of the mo bility and fluctuations in the carrier density inside the channel could not explain the observed noise. We claim that charge fluctuations in the Shock ley-Read-Hall centers found inside the depleted layer below the gate electr ode are likely to be the origin of low frequency noise in GaAs MESFETs. (C) 2000 American Institute of Physics. [S0021-8979(00)10801-1].