OBSERVATIONS OF DISLOCATIONS AND JUNCTION IRREGULARITIES IN BIPOLAR-TRANSISTORS USING THE EBIC MODE OF THE SCANNING ELECTRON-MICROSCOPE

The E.B.I.C. mode of the SEM has been used to study defect structures in bipolar transistors, with particular attention paid to the way in which the presence of the second junction affects the contrast. When the E.B.I.C. signal was collected from the emitter/base junction, a dislocation network giving black contrast was observed for both an open-circuit and short-circuit collector/base junction. However, when the signal was collected from the collector/base junction, black contrast was observed for an open-circuit emitter/base junction and white contrast for a short-circuit junction. It is shown that the white contrast is caused by irregularities in the emitter/base junction, resulting from a local retardation of the phosphorus diffusion at points where dislocations occur. © 1979.