Thermal reaction of Pt film with 〈110〉 GaN epilayer

Abstract

Backscattering spectrometry, x-ray diffractometry, and scanning electron microscopy have been used to study the reaction of a thin Pt film with an epilayer of ͗110͘ GaN on ͗110͘ sapphire upon annealing at 450, 550, 650, 750, and 800°C for 30 min. A Ga concentration of 2 at. % is detected by MeV 4 He ϩϩ backscattering spectrometry in the Pt layer at 550°C. By x-ray diffraction, structural changes are observed already at 450°C. At 650°C, textured Ga 2 Pt appears as reaction product. The surface morphology exhibits instabilities by the formation of blisters at 650°C and voids at 800°C.

Catalytic Activation of Mg-Doped GaN by Hydrogen Desorption Using Different Metal Thin Layers

“…Nevertheless, the sample annealed with Mo has a higher hydrogen concentration than that annealed with Ni, but shows a minimum resistivity with a hole concentration of 5:1 Â 10 17 cm À3 . 10,12) A similar annealing behavior between the Ni film and the p-GaN layer was previously reported by Venugopalan et al, 13) The interfacial reaction may increase the number of impurity-related defects and produce more nitrogen vacancies with the nitrogen diffusion. However, no obvious interdiffusion between Mo and GaN is observed at the interface owing to the strong chemical inertness of the Mo metal.…”

Gd on GaN(0001) surface: Growth, interaction, and Fermi level movement

“…[5][6][7][8][9][10][11][12][13][14][15][16][17][18] The present report describes a study of rareearth ͑RE͒ metals on GaN. RE metals have a low work function and electronegativity, so this kind of investigation may yield valuable information for elucidating the fundamental process involved in the interfacial reaction and SB formation.…”

Performance comparison of Pt/Au and Ni/Au Schottky contacts on Al x Ga 1− x N/GaN heterostructures at high temperatures

“…[6] The 2DEG density of the Pt-treated sample increases after annealing in N 2 ambience at 600 • C. Although GaN does not dissociate in vacuum until above 800 • C, formation of nitrogen is accelerated by the reaction of Pt and GaN to form Ga 2 Pt and N 2 . [9,10] Therefore, we believe that Pt impurity in the annealing will react with adjacent Ga atoms to form Ga-containing compounds, such as Ga 2 Pt, and N 2 . The effective removal of nitrogen from the Al x Ga 1−x N surface appears to be responsible for the forming of N-vacancy (V N ) or/and V N -related complex, which induce the increase of the 2DEG density.…”

“…The possible reason was that once the Ga 2 Pt has formed, the interface becomes quite thermodynamically stable. [10,14] It not only successfully stops the outdiffusion of Ga and N from the substrate, but also essentially prevents the penetration of Pt into Al x Ga 1−x N barrier. Thus, the formation of a highly stable thin layer between Pt and the Al x Ga 1−x N barrier may be the reason for the good thermal stability of the Au/Pt/Al 0.25 Ga 0.75 N/GaN Schottky diodes.…”