Shallow level recombination current dominance in transistor betas

A new recombination mechanism, via the high density of shallow donor and acceptors present in the base-emitter junction of integrated circuit transistors, is suggested. In contrast to the recombination via deep centers, this mechanism has an ideal voltage dependence, leading to a beta essentially independent of the base-emitter voltage. It appears to be the dominant component to the base current of integrated circuit transistors. The temperature dependence of the beta of the transistors arises from the ionization energy of the donors and acceptors. The rate-setting capture cross section by neutral acceptor and donors is 1.3(5)*10/sup -5/ cm/sup 2/.<
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