Zusammenfassung
In thin n-GaAs epitaxial layers current filament patterns formed by low-temperature impurity breakdown have been visualized for different contact geometries. Independent of the contact geometry, after nucleation a generic shape of filaments has been observed in the form of a stripe of high current density with parallel borders whose width is proportional to the sample current. Filament splitting ...
Zusammenfassung
In thin n-GaAs epitaxial layers current filament patterns formed by low-temperature impurity breakdown have been visualized for different contact geometries. Independent of the contact geometry, after nucleation a generic shape of filaments has been observed in the form of a stripe of high current density with parallel borders whose width is proportional to the sample current. Filament splitting processes could be attributed to geometrical properties of the contacts without any inherent critical width. In a magnetic field applied normal to the semiconductor film two different types of stable filament configurations have been found. One can be characterized by a filament deflection in the direction of the Lorentz force acting on the;electrons, the other one by a filament tilting related to the Hall angle. The experimental results are explained in terms of a simple mathematical model.