Figure 4

(a) (b) EMS images of diodes #1CX and #1DX. The inserted images are magnifications of areas near the respective luminous points. In the case of diode #1CX shown in (a), two luminous points, A and B, were observed in conjunction with a reverse leakage current of 500 nA at –120 V. For diode #1DX shown in (b), three luminous points, C, D and E, appeared at a reverse leakage current of 400 nA at –78 V.