Hi Gene, The usually quoted formula is:
IS = A*exp(-Eg/(k*T) Where IS = saturation current, A is nearly constant independent of temperature and dependent on diffusion coefficients of electrons and holes. k is the Boltzmann constant. ν is a constant; 1 for germanium and 2 for silicon; and T is the absolute temperature (deg Kelvin). Eg is the band gap of the semiconductor. The band gap of silicon is 1.12eV and that of germanium 0.66eV. According to this formula, IS doubles for approx 5degC rise in temperature for silicon and 8degC for germanium. However, the reality is somewhat different and a better approximation(i) is this: IS = A*T^m*exp(-Eg/(n*k*T)) Where IS = saturation current, A is a constant independent of temperature and dependent on diffusion coefficients of electrons and holes. k is the Boltzmann constant. T is the absolute temperature (deg Kelvin). m is a constant; 1.5 for silicon and 2 for germanium. n is a constant; 1 for germanium and 2 for silicon Eg is the band gap of the semiconductor. The band gap of silicon is 1.12eV and that of germanium 0.66eV. I think the formula holds for GaAs and other semiconductor junction diodes but the various constant will be different. I'm not sure how IS varies for schottky (metal-semiconductor junction) diodes. This also assumes that the reverse bias is not high enough to cause any zener or avalanche breakdown effects that contribute to the reverse leakage current. Cheers, Andy. www.signality.co.uk (i) Integrated Electronics. Millman and Halkias (International Student Edition) 1972 Lib Cong Cat Card # 79-172657 p752 sect 19.11 2009/12/1 gene glick <carzr...@optonline.net>: > I'm trying to find some info on the temperature variation of the reverse > saturation current of a diode. Anyone know about this? > > gene > > > _______________________________________________ > geda-user mailing list > geda-user@moria.seul.org > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user