| 摘要 |
A method and apparatus for deposition of an in-situ doped silicon film are disclosed. The deposition may be carried out in an LPCVD reactor, with the temperature of the chamber during deposition preferably closely above the decomposition temperature of silane gas. The preferred dopant source is tertiary butyl phosphine, since the deposition rate of in-situ doped silicon using this source is much greater than that using phosphine as the source, which allows low temperature deposition at reasonable rates. At a temperature of about 560 DEG Celsius, the phosphorous is better incorporated into the deposited film than in films deposited at higher temperatures, which allows the ratio of dopant gas to silane in the chamber to be lower; a low dopant ratio allows improved deposition thickness uniformity. The LPCVD reactor preferably has an injector tube therein which travels a distance within the reactor before its opening, through which the tertiary butyl phosphine passes. This allows the tertiary butyl phosphine to be fully heated, and therefore fully decomposed, prior to its introduction into the chamber. Such full decomposition of the dopant source gas further improves the uniformity of the thickness of the deposited film.
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