AVALANCHE MULTIPLICATION NOISE CHARACTERISTICS IN THIN GAAS P(-I-N(+)DIODES())

Avalanche noise measurements have been performed on a range of homojun ction GaAs p(+)-i-n(+) and n(+)-i-p(+) diodes with ''i'' region widths , w from 2.61 to 0.05 mu m. The results show that for w less than or e qual to 1 mu m the dependence of excess noise factor F on multiplicati on does not follow the well-established continuous noise theory of McI ntyre [1], Instead, a decreasing noise factor is observed as w decreas es for a constant multiplication. This reduction in F occurs for both electron and hole initiated multiplication in the thinner w structures even though the ionization coefficient ratio is close to unity. The d ead-space, the minimum distance a carrier must travel to gain the ioni zation threshold energy, becomes increasingly important in these thinn er structures and largely accounts for the reduction in noise,