A two-dimensional model for the lateral p—n—p transistor

A two-dimensional solution of the continuity equation in the base of the lateral p-n-p transistor, including interactions with the substrate and subdiffused layer, is presented for dc excitation. This method is extended to the case of steady-state sinusoidal excitation. Computed and measured results are presented for the frequency dependence of the Short-circuit small-signal current transfer ratios, and comparison of these shows reasonable agreement over the full range of measurements. An approximate equivalent circuit derived from a single-pole fit to the frequency response of short-circuit admittance parameters is inferred to be valid Up to a few megahertz for the device considered.