Threshold Energy for Electron-Hole Pair-Production by Electrons in Silicon

Measurements have been made of the reverse bias required for the onset of multiplication in silicon $p\ensuremath{-}n$ junctions of various widths. A value of 2.25\ifmmode\pm\else\textpm\fi{}0.10 ev is arrived at for the threshold energy for electron-hole pair-production by energetic electrons. There is apparently a slight variation of the threshold energy with crystallographic direction; the directions [100], [110], [111], are listed in ascending order of threshold energies. The ionization rate for electrons is greater than for holes.The maximum phonon drag opposing the acceleration of an electron up to the threshold energy by a parabolic field distribution is equivalent to a field of 5.2\ifmmode\times\else\texttimes\fi{}${10}^{4}$ volts ${\mathrm{cm}}^{\ensuremath{-}1}$.