Integrated circuit model for lateral PNP transistors including isolation junction interactions†

Abstract

Abstract A large signal equivalent circuit for integrated circuit lateral PNP transistors including substrate interactions is presented. The model is useful for d.c, linear and non-linear transient time circuit analysis. Measurement methods to determine equivalent circuit parameters are presented. These consist of transistor d.c. current voltage relationships, current gain and small-signal cut-off frequency measurements in various transistor operating modes. The short-circuit current transfer ratio is shown to vary with frequency as 1/ffor the thin epitaxial transistor and as 1/√f for the thick epitaxial transistor. The equivalent circuit of a typical integrated lateral PNP—P substrate transistor (emitter: 50 μm dia., emitter-collector mask separation: 12·5 μm, lateral base width : approx. 6 μm, junction depth : 2·7 μm, epitaxy : resistivity 0·47 ohm-cm, epitaxial layer thickness : 6·4 μm) is determined. The validity of this equivalent circuit is confirmed by comparing the transient time response measurem...