Current Saturation in the Evaporated GaAs Films
A. Yamashita, T. Tuzaki, T. Yamada, I. Yamauchi
Current saturation in evaporated GaAs films was observed. Thin GaAs films were fabricated by means of simultaneous evaporation of the elements of the highest purity onto the metal substrate of the Ta. Electrical characteristics of the films were measured employing the Au electrode evaporated on the GaAs films. The intensity ratio of GaKα/AsKα grows with increase of the Ga temperatures and decreases with increase of the As temperatures. The films in which current saturation was observed are formed approaching the stoichiometric structure, and exhibit n-type conduction. X-ray measurements of the crystallized GaAs films show the (111), (220), and (311) lines. Absorption threshold on the crystallized GaAs films was obtained at about 1.24 eV and approaching the transmission data of bulk GaAs after Sturge. The lowest resistivity measured about 1∼10 Ω·cm. The values of threshold voltage linearly grows with increase of the thickness of the GaAs films. Accordingly, we presumed that phenomena of current saturation in the films could be explained by the two-valley model. © 1967 The American Institute of Physics.
