The ionization rates for holes and electrons in silicon have been determined over the following ranges of field: for holes, (2.5-6.0)×${10}^5$ volts ${\mathrm{cm}}^{-1\mathrm{}}$; for electrons, (2.0-5.0)×${10}^5$ volts ${\mathrm{cm}}^{-1\mathrm{}}$. The ionization rate for electrons is higher than that for holes. The results suggest that the field dependence of the ionization rate for holes and, probably, for electrons also, can be expressed by $a\exp (-\frac{b}{E})$, where $E$ is the field. The constants $a$ and $b$ are different for electrons and holes.

• Received 22 October 1957

DOI:https://doi.org/10.1103/PhysRev.109.1537