Measurement/calibration technique for nanometer scale average film thickness on atomically rough surfaces developed.Current magnetic hard disks are protected by a nanometer-thick layer of alcohol functionalized perfluoroakylether and carbon overcoat. Achievement of higher areal density The number of bits per square inch of storage surface. It typically refers to disk drives, where the number of bits per inch (bpi) times the number of tracks per inch (tpi) yields the areal density. requires further reduction in the space between the head and the magnetic layer at higher speed. The possibility of occasional impacts from head disk collisions requires that the adhesive strength of the organic molecules be increased while retaining the mobility of some of the molecules. One possible solution is to use a mixed molecular assembly in which two separate species are assembled together to impart both adhesive strength and mobility. Because of the poor solubility characteristics of perfluoroakylethers, such mixed films are very difficult to achieve. Hydrocarbon molecules can be used for this purpose. One technical barrier is the measurement of average film thickness at 10 [Angstrom angstrom (ăng`strəm), abbr. Å, unit of length equal to 10−10 meter (0.0000000001 meter); it is used to measure the wavelengths of visible light and of other forms of electromagnetic radiation, such as ultraviolet ] [+ or -] 1 [Angstrom] on a surface with 15 [Angstrom] to 25 [Angstrom] peak-to-valley distance. There is no widely accepted analytical technique An analytical technique is a method that is used to determine the concentration of a chemical compound or chemical element. There are a wide variety of techniques used for analysis, from simple weighing (gravimetric) to titrations (titrimetric)to very advanced techniques using for measuring this thickness accurately and consistently. To address this issue, a master calibration sample was created by depositing a known mass of hydrocarbon molecules in a dilute solution on magnetic hard disk surfaces and allowing the solvent to evaporate slowly. Knowing the mass of the film and the bulk density of the material, the thickness of the film can be calculated. To achieve uniformity of deposition and evaporation, it was necessary to confine the solution to a known area and to overcome the wetting and meniscus meniscus /me·nis·cus/ (me-nis´kus) pl. menis´ci [L.] something of crescent shape, as the concave or convex surface of a column of liquid in a pipet or buret, or a crescent-shaped cartilage in the knee joint. forces during the deposition and evaporation processes. A barrier film was used to define the area. Then, the solution was frozen and the solvent was allowed to evaporate slowly under a controlled atmosphere A controlled atmosphere is an agricultural storage method. An atmosphere in which oxygen, carbon dioxide and nitrogen concentrations are regulated, as well as temperature and humidity. Two major classes of commodity can be stored in controlled atmosphere. 1. . The procedure was carried out in a clean room to minimize potential contaminants. This technique has been used successfully to deposit films with a range of hydrocarbon thickness from 3 [Angstrom] to 25 [Angstrom], using disks of different roughness (isotropic Refers to properties that do not differ no matter which direction is measured. For example, an isotropic antenna radiates almost the same power in all directions. In practice, antennas cannot be 100% isotropic. and anisotropic Refers to properties that differ based on the direction that is measured. For example, an anisotropic antenna is a directional antenna; the power level is not the same in all directions. Contrast with isotropic. ), different carbon overcoat thickness, and different carbon overcoat chemistry (hydrogenated carbon, nitrogenated carbon, and a mixed hydrogenate/nitrogenated carbon). Consequently, this method can be applied to a variety of engineering surfaces for film thickness measurement, and it can be used to calibrate To adjust or bring into balance. Scanners, CRTs and similar peripherals may require periodic adjustment. Unlike digital devices, the electronic components within these analog devices may change from their original specification. See color calibration and tweak. different analytical techniques used for such measurements. CONTACT: Richard Gates, (301) 975-3677; richard.gates@nist.gov or Stephen Hsu, (301) 975-6120; stephen.hsu@nist.gov. |
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