Impact ionization in submicron silicon devices

Abstract

Photomultiplication initiated by electrons and holes has been measured in submicron Si p+–i–n+ and n+–i–p+ diodes with nominal intrinsic region thicknesses between 0.8 and 0.1 μm. A local analysis of the thinner devices gives values of the electron and hole ionization coefficients (α and β, respectively) smaller than those in the literature, especially at low values of multiplication because of dead space effects. The dead space in Si appears to be less significant than in GaAs structures of similar dimensions.