Micro-plasma model of "Popcorn noise"

"Popcorn noise" has been observed in integrated operational amplifiers and isolated to specific input transistors. These transistors have been studied in depth physically and electrically, and have been observed to have negative resistance regions in the reversed biased collector-base characteristic. These regions were studied by the methods of Chynoweth and MeKay (1) in the pre-breakdown region and Ricks and Pope in the post breakdown region (2). In all of the several hundred devices studied (obtained from three different vendors), negative resistance regions or multiple current levels were found to exist. Devices which do not exhibit "popcorn noise" do not possess these negative resistance regions. Further investigations have shown that localized light emission is observed emanating from within the vicinity of the collector-base depletion region when the transistor is biased into a negative resistance region of the volt-ampere characteristic. These localized plasmas were observed to be white or slightly yellow-white in color. The light emission occurs simultaneous with the observance of "popcorn noise." These results are strongly suggestive that "popcorn noise" and microplasma noise are equivalent.