Excess Noise in Selected Field-Effect Transistors

The origin of excess noise in high-quality FETs is investigated in the frequency domain. It is found that, for use in opto-feedback systems, generation-recombination noise through deep traps is important. It is shown that best initial characterization of transistors for that use can be done in a grounded gate configuration. The activation energy of the principal traps responsible for the g-r noise is calculated and tentative identification of the responsible impurities or defects is made. It is also shown that the basic low temperature limit of Si FET operation is set by majority carrier freeze out at chip temperatures well above 100K and that boron nitride mounts at temperatures above 77K can contribute 10 to 15 eV of 1/f noise.