Kinetic Study of the Oxidation of Gallium Nitride in Dry Air

Abstract

The oxidation of polycrystalline GaN powder and GaN epi layers in dry air has been investigated. Bulk 0-20 X-ray diffraction (XRD) revealed no evidence of oxide formation on the powder specimen exposed to temperatures of up to 750 °C for 25 h. However, when oxidized at temperatures of 900 °C or greater for 1 h or longer, an oxide was observed to form and was identified as the monoclinic 3-Ga203, the same oxide observed previously by the present investigators to form on epitaxial GaN films. Information regarding the oxidation kinetics was obtained in the present study by measuring the intensity of the f3-Ga203, (2 1 7) XRD peak as a function of oxidation time at various temperatures, and the initial stage of the oxidation was found to be limited by the rate of an interfacial reaction with an activation energy of --3 X 1 0 J/mol. An interfacial reaction-controlled mechanism was also observed to limit the rate of oxidation of GaN epi layers at 900 °C.

Generation of Charged Nanoparticles During the Synthesis of GaN Nanostructures by Atmospheric-Pressure Chemical Vapor Deposition

“…However, a very large amount of oxygen was detected reproducibly. The oxygen might be formed by oxidation and absorption in the air when the sample was taken outside as suggested by Wolter and Tang (Wolter et al 1998;Tang et al 2003). Although the EDS is not accurate especially in the analysis of light elements, it poses a possibility that the GaN crystals formed in the reactor might be deficient in nitrogen and the excess Ga is oxidized in the air after the process.…”

Testing the Temperature Limits of GaN-Based HEMT Devices

“…In oxygen, Ga 2 O 3 will form widely, passivating the surface [24]. The thermal and chemical stability of the GaN buffer layer surface outside the active device mesa, usually by silicon nitride (Si 3 N 4 ), will therefore strongly depend on its passivation properties.…”

Thermodynamics, structure and kinetics in the system Ga–O–N

“…the conversion of GaN to Ga 2 O 3 starts immediately, with the maximum reaction rate at the beginning of the reaction. We modeled this kinetics using a layer growth model which was applied by Wolter et al [47] to explain the oxidation of GaN epilayers. In our case -oxidation of GaN grains -the reaction front moves from the surface of the GaN grains into the interior, i.e.…”