GaAs FET'a WITH A FLICKER-NOISE CORNER BELOW 1 MHz.

GaAs MESFETs with significantly reduced low-frequency noise are demonstrated through application of an understanding that the dominant noise source is generation-recombination (g-r) noise from deep level traps in the gate and backside depletion layers. A 1/f noise spectrum measured from 100 Hz to 10 MHz is modeled as the sum of Lorentzian noise spectra from a few traps subject to the temperature distribution inherent in a GaAs MESFET. The noise associated with a single midbandgap trapping level does not appear as an ideal Lorentzian, but rather as 1/f over nearly a decade frequency range by virtue of a time constant that is a strong function of temperature (exp left bracket E//a/kT right bracket ) and an estimated temperature distribution of 22 degree C across the active region. The major g-r trap was characterized as having an activation energy of 0. 75 eV. By reducing the g-r noise, flicker noise was decreased by more than 15 dB compared to conventional GaAs MESFETs and the noise corner was reduced to less than 1 MHz from a typical 40 MHz. This significant reduction was achieved by using molecular-beam epitaxial layers designed to have lower trap concentrations and high channel doping. These results are within 10 dB of the estimated 1/f noise limit due to the quantum mechanics of carrier scattering.