Are Germanium Zener diodes still obtainable

I need a Germanium Zener diode for a shot noise generator circuit. If I am correct, Silicon replaced Germanium for use in diodes and other semiconductors because of the fact that Germanium diodes have a much higher reverse leakage and are much noisier. But due to the smaller band gap of Germanium as compared to Silicon, this makes them more useful in shot noise generators since at the Zener voltage, a Germanium Zener diode has a depletion region that is smaller than the electron wavelength and as electrons tunnel through it, their energy levels spread out due to the uncertainty principle.