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].