OBSERVATION OF A LARGE-SCALE SHEETLIKE CURRENT FILAMENT IN A THIN N-GAAS LAYER

Spatial patterns of a large-scale sheetlike current filament formed during low-temperature avalanche breakdown have been investigated in a thin epitaxial n-GaAs layer using the low-temperature scanning electron microscope. The sheetlike current filament was nucleated between planar-type ohmic contacts due to impact ionization of neutral shallow donors. The width of the current filament (200 ~ 700 µm) was measured as a function of the sample voltage in the postbreakdown regime. A turbulent pattern observed in the beam-induced firing wave instability has also been measured. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.