Interferometric measurements of the diameters of a single‐crystal silicon sphere
| Autor: | G. Zosi, K. Fujii, K. Nakayama, M. Tanaka, Y. Nezu, R. Masui |
|---|---|
| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Review of Scientific Instruments. 63:5320-5325 |
| ISSN: | 1089-7623 0034-6748 |
| Popis: | A new interferometer has been developed for the accurate determination of the density of a silicon crystal, in which a single‐crystal silicon sphere of nearly perfect geometry is placed in a Fabry–Perot etalon of accurately known plate distance, and the diameters are obtained by measuring the two gaps between the etalon and the adjacent surface of the sphere. A new method is used to measure the sum of the length of the two gaps by scanning the etalon against the sphere. Two wavelengths, 633 nm from a frequency‐stabilized He–Ne laser and 441 nm from a free‐running He–Cd laser, are used to determine the order of interference by applying the method of exact fractions. The diameter of about 94 mm has been measured with a resolution of 0.5 nm. Diameter measurements from uniformly distributed directions have shown that the mean diameter has been determined with a standard deviation of 8.6 nm, corresponding to 0.28 ppm in the volume determination. The total uncertainty of the volume is estimated to be 0.34 ppm. Effects of a thin oxide layer and impurities on the bulk density are discussed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|