“…However, the technique we have used will allow specific devices, NPN or PNP, to be optimised, if required. In many ways this "sacrificial oxidation" technique is analogous to that of the "selective implanted collector" (SIC) but, we believe, has the advantage of superior control, manufacturability and flexibility [3], [4]. Figure 10 shows an SEM micrograph of an NPN transistor during processing.…”