Thin NPN Base Formation Using High-Pressure Oxidation and Poly-silicon Emitter

The performance of a bipolar transistor is governed, in part , by the base transit time. Thus, to increase the bipolar transistor speed, a narrow basewidth, as well as a shallow emitter junction depth, is required. Processes to fabricate such shallow junction bipolar devices, particularly for BiCMOS applications, are well documented [1-3]. Examples of typical base processes are: 1) implantation of boron or BF sub 2 through the base oxide; 2) deposition of the base oxide after the base implant; 3) low temperature in-situ doped epitaxy.