Avalanche Breakdown in Gallium Arsenidep−nJunctions

Charge multiplication and avalanche breakdown have been studied in relatively narrow diffused $p-n$ junctions in GaAs. For these studies both junctions with and without microplasma effects were available. From the charge multiplication studies in microplasma-free junctions, the ionization rate, $\alpha$, has been determined as a function of the field, $\mathcal{E}$. These results are unusual in that they give a decidedly better fit to Wolff's theory than to Shockley's; this is found to be consistent with the criterion, $e\mathcal{E}\lambda >(\mathrm{o}\mathrm{p}\mathrm{t}\mathrm{i}\mathrm{c}\mathrm{a}\mathrm{l}-\mathrm{p}\mathrm{h}\mathrm{o}\mathrm{n}\mathrm{o}\mathrm{n}\mathrm{e}\mathrm{n}\mathrm{e}\mathrm{r}\mathrm{g}\mathrm{y})$, discussed in a more recent theory due to Baraff which combines the approaches of both Wolff and Shockley. From detailed comparisons with Baraff's theory, the mean free path, $\lambda$, for the hot carriers between collisions involving optical phonon emission is 15±2 Å and the threshold energy for pair production is 1.7±0.3 eV.