Patent ID: 7294207
Filing Date: 2007-11-13
Classification: C23C,C30B

Abstract:
1. Gas-admission element for a device for depositing in particular crystalline layers on in particular layers on in particular crystalline substrates, by means of which two process gases can be introduced into a process chamber of a reactor separately from one another above a heatable susceptor, the gas-admission element having a central feed line with a central end-side outlet opening for a first process gas, and having a peripheral line which is peripheral with respect to the central feed line that flows a second process gas into an annular antechamber surrounded by a rotationally symmetrical gas-permeable gas-discharge ring, the second process gas emerges through the rotationally symmetrical gas permeable gas-discharge ring, the radial width of the annular antechamber decreases toward the free end of the rotationally symmetrical gas permeable gas-discharge ring, on account of a gas-guiding surface which does not run parallel to the central axis in longitudinal section, characterized by a frustoconical or rotationally hyperboloid-shaped gas-guiding surface, which is formed by the gas-guiding surface, for convective cooling of the portion of the rotationally symmetrical gas-permeable gas-discharge ring which is close to the susceptor, by means of the second process gas flowing along the gas-guiding surface.