Dose Enhancement at the Emitter Interface of a Bipolar Junction Transistor

This paper constitutes a first step toward solving the genuinely difficult problem of relating electronic circuit performance to the fundamental parameters of the device fabrication process. In particular, this work provides an in-depth analysis of radiation dose enhancement as might be observed, for example, at the emitter contact-bulk emitter interface of a bipolar junction transistor. A closed-form approximate solution to the charge continuity equation demonstrates that (1) the radiation-induced excess carrier density profile is maximized within two diffusion lengths of a dissimilar interface, and (2) impure interfaces, as measured by carrier recombination velocity, can dramatically neutralize the undesired electrical effects of significant dose enhancement.