A vitreous native oxide can be grown on normalGaP by oxidation in a concentrated solution of hydrogen peroxide, and this oxide effectively passivates normalGaP light‐emitting devices. This paper reports the first electrical characterization of this native oxide. Electrical measurements were performed on MOS structures prepared by growing a native oxide film 500–1000AÅ thick on the false(true111¯false) face of an n‐ or p‐type normalGaP wafer and evaporating an Au field plate on the oxide. The refractive index of the oxide film was 1.58. Current‐voltage and capacitance‐voltage characteristics show that the native oxide is an electrical insulator, with a low frequency dielectric constant ε≈5.5 , and a dielectric breakdown strength of 6–8×106V/normalcm after annealing in nitrogen at 250°C. Current‐voltage behavior shows a linear dependence of In J normalon E½ , typical of field‐enhanced thermionic emission. The I‐V characteristics are nonsymmetric with respect to field plate polarity, suggesting the conduction mechanism to be surface‐barrier‐controlled emission, with a barrier height φnormalb≈1.2 normaleV , as determined from the temperature dependence of the I‐V characteristics. The dielectric constant determined from the slope of the I‐V characteristics by using a field‐enhanced thermionic emission model agrees with the value obtained from capacitance measurements. Capacitance‐voltage characteristics show accumulation and deep depletion behavior. Analysis of deep depletion curves yields a surface charge density Qnormals≈4×1012/cm2 for both p‐ and n‐type normalGaP samples. Values of |ND−NA| for the normalGaP substrates obtained from deep depletion data are in good agreement with the values obtained from Hall measurements on the substrate material.

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Es wird eine Methode zur vollständigen Anodisierung von GaAs‐Oberflächen bis zu einer Oxidschichtdicke von ≈︁ 8600 Å entwickelt.

Anodic oxidation of GaAs is examined and a technique for growing full surface oxides ~ 86G,0A thick is reported. Anodization in a hot, concentrated (30%) H202 electrolyte of pH ~-2 using self-anodizing metal contacts is found to yield uniform oxides with a refractive index of 1.8 and a growth rate ranging from 22 to 50 A/V. The as-grown oxide will etch in HC1 and H20. Chemical stability of this oxide is enhanced with baking in dry nitrogen and after 2 hr at 250~ H20 will no longer etch the oxide; after 1 hr at 600~ HC1, HF, HNO3, NI-I4OH will not etch the oxide but hot HsPO4 will etch the oxide. The oxide is an amorphous, vitreous film which crystallizes to ~-Ga20~ after several hours at 800~ A thin (<100A) graded, oxide-GaAs interface was found to grow at anodization potentials >100V and for heat-treatment at temperatures greater than 400~ for 1 hr. The oxide exhibits excellent adherence to the substrate, has good match with the thermal coefficient of expansion of GaAs, and forms a relatively strain-free interface. Since GaAs is consumed during anodization, this provides a technique for surface cleaning using an oxide growth-strip step. Enhanced device reliability is expected to result by utilization of the oxide growth-strip-regrowth cycle during device fabrication, since this will remove contamination from the surface. The findings here enumerated, coupled with ease of oxide growth, suggest ready implementation to a GaAs planar technology.

This paper reports the first use of an amorphous native oxide on gallium arsenide to mask against zinc diffusion. Anodic oxides were grown at low temperature (≤100°C), and stripes were defined in this oxide using standard photolithographic processing. These samples were diffused, after an appropriate annealing cycle, in a closed system using a zinc source ( Zn 3 As 2 + GaAs ) at 612°C for times up to 2 hr. Diffusion depths were measured using a lap and stain procedure, and the results showed the oxide to be effective as a zinc barrier. Furthermore, no anomalous lateral underdiffusion was observed indicative of a high integrity interface between the oxide and semiconductor.