Physical investigation of the mesoplasma

The study of the mesoplasma as the fundamental model for second breakdown has been pursued by a variety of physical techniques. The conviction that a melt forms at or near the junction was strengthened by the microscopic, observation of molten globules of silicon on silicon diode surfaces under certain experimental conditions. Lapping and staining techniques were used to search the junction region for evidence of various kinds of damage and for information on the size and shape of regions affected by heat. The time dependence of light emission from the mesoplasma region in relation to electrical changes was studied. The light emission lags behind the onset of second breakdown and lingers on after the current through the device is shut off. Some work was done on the temperature dependence of the electrical characteristics of second breakdown. As far as possible, an attempt has been made to compare the physical results with the quantitative predictions of a computed model, with rather satisfactory correlations.