The temperature dependence of ideal gain in double diffused silicon transistors

It has been demonstrated that the base current of planar silicon transistors can be separated into a non-ideal and an ideal component. This paper will neglect the non-ideal component. For transistors with transport factors (β) approaching unity, the ideal component is approximately equal to the minority carrier current injected into the emitter. The resulting gain (hereafter called ideal gain) has the form hFE(ideal) - IC/IpEwhere IpEis the hole current injected into the emitter of an npn transistor. Both components obey the well-known exponential law: I = I^oexp (qVEB/kT) A large temperature dependence of ideal gain can be observed on double diffused planar transistors. The ideal gain on the other hand shows no temperature dependence. This indicates that the temperature coefficient of the injected minority carrier currents are different in the emitter and base regions, while those in the base and collector regions are identical.