METHOD FOR MEASURING PHOTOCONDUCTIVITY OF HIGH- RESISTANT SEMICONDUCTORS Russian patent published in 1995 - IPC

FIELD: measuring electric characteristics of semiconductors. SUBSTANCE: method involves exposition of semiconductor by interference pattern, which is generated by reference and phase-modulated signal beams. Phase modulation is done by two frequencies F and f and f₁, frequency f₁ conforms to equation , where ^τd_i is time of dielectric relaxation of exposed light, τ is life time of light-inducted current carriers. This results in high value of output signal-to-noise ratio at frequency f. Photoconductivity is calculated by characteristic trailing edge frequency of dependence of output signal on frequency and by diffusion length of transfer of light-inducted current carriers. Latter length is calculated by dependence of output signal amplitude on three-dimensional frequency of interference pattern. EFFECT: increased sensitivity. 3 dwg