Characterization of Emitter-Collector Shorts by Anodization, Voltage Contrast Sem, and Tem

Chemical anodization and voltage contrast scanning electron microscopy (VC-SEM) have been used to identify electrically faulty structures in a bipolar test array. Direct comparison of these techniques was achieved by examining the same emitters with each method. VC-SEM is shown to be a useful technique for delineating E-C shorts because of its nondestructive and purely electrical nature. Further investigations by transmission electron microscopy revealed dislocations in many short-circuited emitters and occasionally in unshorted devices. This confirmed prior observations that crystallographic defects in silicon devices may sometimes be, but are not always, electrically active.