Switching effects have been observed in the current vs voltage curves ofn‐type GaAs diodes with resistivities between 0.3 and 5 &OHgr;‐cm. After switching, the diodes go into a constant‐voltage avalanche breakdown state with a sustaining field of 4500 V/cm. These effects are attributed to a peak in the hole generation rate &agr; between 3,000 and 10,000 V/cm caused by high energy electrons in the (000) valley of the conduction band.