ELECTRON-BEAM INDUCED INSTABILITY DURING FILAMENTARY CURRENT TRANSPORT IN N-GAAS

We report experimental investigations on the current transport of n-GaAs under the conditions of impact ionization avalanche breakdown at low temperatures. The spontaneous formation of a single current filament was observed by means of low-temperature scanning electron microscopy. An electron-beam induced instability occurs at the onset of filamentation. We demonstrate this instability to be due to the local disturbance at the boundaries of the current filament. Our results are compared to the similar behavior of n-GaAs under IR irradiation (firing wave instability). © 1990 Springer-Verlag.