Carrier injection into the substrate of GaAs MESFET structures

The temperature analysis of the excess current, flowing in GaAs MESFET's structures after saturation, indicates that carrier multiplication phenomena must occur within the active layer and the interface to cause the substrate current. This current is proportional to V
DS
rather than to
\squrt{V_{DS}}
. The negative temperature gradient of the excess current is ten times higher than that of the saturation current. Noise measurements reveal the onset of avalanche.