Electron-beam-induced conductivity in self-organized silicon quantum wells

Electron-beam diagnostics are used to study self-organized quantum wells which form within ultrashallow silicon p(+)-n junctions under the conditions of nonequilibrium boron diffusion. The energy dependence and current-voltage characteristics of the electron-beam-induced conductivity are investigated with relative dominance of both longitudinal and transverse quantum wells, which are oriented parallel and perpendicularly to the p-n junction plane, respectively. Current-voltage characteristics of the electron-beam-induced conductivity are exhibited for the first time with both reverse and forward biasing of the silicon p(+)-n junction. This became possible because of the presence of self-organized transverse quantum wells within the ultrashallow p(+) diffusion profile, while self-organized longitudinal quantum wells promote the appearance of electron-beam-induced conductivity only when the p(+)-n junction is reverse-biased. The distribution of the probability for the separation of electron-hole pairs across the thickness of the crystal derived from the energy dependences of the electron-beam-induced conductivity reveals effects of the avalanche multiplication of the nonequilibrium carriers as a result of the spatial separation of electrons and holes in the field of a p(+)-n junction that contains self-organized transverse quantum wells. (C) 1999 American Institute of Physics. [S1063-7826(99)01807-4].