A method for the measurement of the diffusion length and the pn product in silicon

A new method is described for the measurement of the diffusion length and pn product in silicon. The measuring method is based on the measurement of the I-V characteristics of different lateral bipolar transistors fabricated on the same wafer under the same processing conditions. The emitters of these transistors are exactly similar and function only as an injecting boundary to the base regions when they are forward biased. Therefore, the electronic properties of the emitters are irrelevant. The method has been analyzed theoretically and experimentally. The results have been compared with the results of other common measuring methods and good agreement has been obtained. The method is characterized by its simplicity. Also, it has the advantage that the diffusion length and the pn product are determined in the same region of the same device.