Measurement of minority carrier diffusion length and lifetime in SOI devices by flying spot laser scanner as a function of residual misfit

The recombination properties of minority carriers determine the basic electronic properties of SOI materials and control the performance of a variety of SOI devices. Knowledge of the minority carrier recombination characteristics and its correlation to residual defect density is important for the evaluation of SOI technologies with varying degrees of crystal lattice imperfection. In this work we first describe a technique based on a flying spot laser scan microscope for the measurement of minority carrier diffusion length, L, and lifetime, τ, in SOI high voltage diodes. In our experiment, laser light of 633 nm wavelength is absorbed in the Si material through the generation of electron-hole pairs which, if generated in the depletion region, are separated by the high local field to give rise to a photocurrent that can be measured