Analytical model of low-frequency diffusion noise in GaAs MESFETs

A simple analytical formula for the low-frequency noise (below 10 kHz) in GaAs MESFETs is derived. This unipolar model describes noise generated in the semi-insulating substrate and involves diffusion, drift, and generation-recombination due to deep-level traps. The derived noise spectrum is diffusion-like and rolls off as f/sup -3/2/ at the high-frequency limit. The results are formally identical to the conventional diffusion/drift noise spectrum except the diffusion/drift constants are replaced by their reduced counterparts. Good qualitative agreement with experiments has been obtained for temperature, length, and field dependences. The derived spectrum can be computed quickly and is suitable for use in circuit simulation of low-frequency performance of MESFETs.<
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