Aluminum Oxidation in Water

Abstract

Water rinse of aluminum metallized integrated circuits must be carefully monitored because the A1 can oxidize rapidly under certain conditions. A1 oxidation in 10 IVIft deionized water was therefore studied using Auger spectroscopy, and transmission and scanning electron microscopies, to investigate the oxide growth as a function of water temperature and rinse time, use of photolithography, and Cu-doping of the AI. A1 oxide thicknesses were 20-30A before any treatment and were 35, 70, and ---~3000A after 5 rain rinses in 40 ~ 60 ~ and 80~ water, respectively. Photolithography and Cu doping induced no large effects. In 40~ water, little oxidation occurred for 20 rain and rapid oxidation began after 40 rain, especially at nucleation sites with C and Si contamination. The oxide grown in water has a porous structure, is nearly amorphous, and contains gamma-alumina and hydrated oxides. Near 80~ several thousand angstroms of oxide can grow in minutes.

Aluminum Etching in Carbon Tetrachloride Plasmas

“…indicated that a l u m i n u m films could be plasma-etched in CC14 using a l u m i n u m electrodes without significant polymer formation, although the reproducibility of this procedure is questionable. In order to minimize attack of the electrode material, a l u m i n u m electrodes were oxidized in hot (60~176 DI water (8) to increase the surface oxide thickness. Since this process greatly improved the reproducibility of the etch rate data, and little or no polymer was observed on the electrode surfaces, a l u m i n u m electrodes were anodized in an aqueous sulfuric acid solution (15% by volume) under constant current conditions to a thickness of ,-.10 #m.…”

“…Recombination on the wall or in the gas phase of the various fragments indicated in Eq. [3] and [4] then generate the observed products in the cold traps (along with unreacted CCl4) CCla + CCI~--> C2C1~ [5] CI + C1 ~ CI2 [6] CC13 + C12-> CC14 + Cl [7] CC12 ~-CC12-> C2C14 [8] The chlorine radical, as generated by Eq. [3], [4], and [7], is probably responsible for aluminum etching, as proposed previously (3,6,7).…”

Realization of a high mobility dual-gated graphene field-effect transistor with Al2O3 dielectric

“…Based on the X-ray photoelectron spectroscopy (XPS) and electrical measurement results, the Al nucleation layer is completely oxidized as soon as the sample is exposed in air to be transferred to ALD chamber 14 . In addition, the initial stage of ALD growth starts with an H 2 O oxidizing cycle at elevated temperatures to further complete the oxidation step 15 .…”

Template-Stripped Ultra-Smooth Aluminum Films (0.2 nm RMS) for the Surface Forces Apparatus

“…Oxidation of the freshly exposed Al surface by water creates a low-density oxide layer, which renders the Al film labile to corrosion. 45,46 AFM data recorded on a TS-Al surface that was not heated after template stripping show many small holes, which we associate with etch pits. The presence of these pits suggests that the surface oxide formed in water does not prevent further detrimental surface oxidation (corrosion).…”