Galvanostatic Anodization of GaAs in Methanolic  KOH

Abstract

The galvanostatic anodization of n‐type normalGaAs in methanolic KOH concentrations of 0.05, 0.20, and 0.50N has been studied. We report measurements of the growth constants, current efficiencies, oxide density, and dielectric strength. With the exception of oxide density these parameters are found to depend on the electrolyte concentration. It will be shown that oxides grown in the 0.2N electrolyte have the most reproducible growth parameters, and gravimetric measurements on these oxides coupled with a sectioning technique permit a direct measurement of the oxide density which is found to be 4.78 g/cm3. Furthermore the dielectric strength of this oxide ranges between 4 normaland 5×106V/normalcm and appears to be independent of surface treatment or oxide annealing.

Cation and Anion Transport Numbers in Anodic GaAs Oxides

“…been shown that crystalline imperfections have a detrimental effect on electronic properties of SOS films, such as excess carrier lifetime, trapping centers, degree of amorphization, and microscopic electrical inhomogeneities (1)(2)(3).…”

“…Not surprisingly the oxide of GaAs has also received considerable attention. Many studies have characterized the oxidation kinetics in a variety of electrolytes (1)(2)(3) and have measured the oxide composition profile (4)(5)(6). The electrical properties of the oxide and the oxide-semiconductor interface have also been reported in the literature (3,5,7,8).…”

“…Many studies have characterized the oxidation kinetics in a variety of electrolytes (1)(2)(3) and have measured the oxide composition profile (4)(5)(6). The electrical properties of the oxide and the oxide-semiconductor interface have also been reported in the literature (3,5,7,8). Unfortunately these studies have shown that the native GaAs oxide is inferior to that of SiO~.…”

A Surface Infrared Study of the Liquid Methanol‐Gallium Arsenide Interface

“…The methanolic KOH-gallium arsenide systera.--The gallium arsenide surface was next examined under 0.05N methanolic potassium hydroxide, an electrolyte which has been used in anodic oxidation studies (3). The spectrum of the wafer surface recorded in situ under the liquid electrolyte closely matched the spectrum collected previously under pure methanol.…”

“…Organic-based solutions are also routinely employed in semiconductor research as anisotropic and crystallographic (defect delineation) etchants (1,2). In addition, it has been demonstrated that gallium arsenide can be anodized in organic electrolytes to produce an insulating oxide surface layer (3). In this study, the gallium arsenide surface was investigated in situ under exposure to methanol and 0.05N methanolic potassium hydroxide.…”