CHARACTERIZATION OF BREAKDOWN PHENOMENA IN LIGHT-EMITTING SILICON N+PDIODES

A 10 kV, 10(-10) A focused electron beam was used to map localized cha rge multiplication, and localized avalanche breakdown sites in the dep letion region of light emitting silicon n(+)p junctions. It was observ ed that the localized avalanche breakdown sites led to the formation o f large densities of extremely small current filaments in the junction . The dimension of each filament was well into the submicron range (10 0-150 nm in diameter) and the densities of the filaments varied latera lly across the junction between 4 x 10(8) and 4 x 10(10) cm(-2). Accur ate and high resolution maps of the current filaments could be obtaine d. The formation of the individual current filaments (microavalanche s ites) at a submicron level are apparently related to localized defect and materials effects. The distribution of the current filaments at th e micron level relates to the strength and distribution of electric fi eld at the junction interface. Direct evidence has been obtained that the nonuniformities in the light emission patterns on a larger scale ( 10-100) microns are controlled by dopant striations on the lower doped p-side of the diode junction. (C) 1998 American Institute of Physics. [S0021-8979(98)04017-1].