ACCURATE EXTRACTION OF THE DIFFUSION CURRENT IN SILICON P-N-JUNCTION DIODES

An accurate method for the extraction of the reverse diffusion current component in a silicon p-n junction diode is proposed. It combines ca pacitance-voltage and current-voltage measurements on an array of diod es with different geometry in order to separate the peripheral and the volume leakage current components. The corrected volume capacitance i s then used to calculate the depletion width as a function of the reve rse bias. Extrapolation of the reverse current to zero depletion width results in the diffusion current part, both for the volume and for th e peripheral component. From the temperature dependence, a thermal act ivation energy of 1.12 eV is obtained. The volume diffusion current de nsity of the p-type Czochralski wafers studied, shows a pronounced sub strate dependence, while the peripheral diffusion current density is c onstant. Finally, the implications for the extraction of the effective bulk recombination lifetime are discussed. (C) 1998 American Institut e of Physics.