1/f trapping noise theory with uniform distribution of energy‐activated traps and experiments in GaAs/InP MESFET’s biased from ohmic to saturation region

The theory of the number‐fluctuation 1/f noise due to a uniform distribution of energy‐activated traps is presented for the first time with a clear experimental support. The expressions of the drain current noise are derived as a function of an effective density of traps at the channel‐buffer interface, taking into account electrical and technological parameters of the GaAs MESFETs biased in the ohmic region as well as in the nonohmic region. In the ohmic region, the drain current noise is proportional to VDS and independent of gate bias, and correlation between the calculated effective density of traps and structural quality of GaAs layers has been observed. In the non‐ohmic region, the drain current noise increases with VDS and becomes constant in the saturation region, which is mainly related to the variations of the channel resistance with drain bias.