LOW-FREQUENCY NOISE IN 4H SILICON-CARBIDE

The bulk low frequency noise has been investigated in the 4H silicon c arbide polytype. In the temperature range of 300-550 K the noise spect ral density S is proportional to f(-1.5), where f is the measurement f requency. A very low noise level has been observed for the bulk noise. At 300 K, the Hooge constant alpha is as small as (2-4)X10(-6) at f=2 0 Hz and alpha less than or equal to 5X10(-7) at f=1300 Hz. At T great er than or equal to 600 K, the generation-recombination noise of a loc al level makes the main contribution into the total low frequency nois e. The electron capture cross section sigma of this level depends very strongly on temperature. In the temperature range of 620-700 K, the t emperature dependence of sigma can be expressed as sigma similar to ex p(-E(1)/kT), with an activation energy E(1) as high as 2.7 eV. (C) 199 7 American Institute of Physics.