Chemical vapor deposition flow inlet elements and methods

Abstract

A flow inlet element for a chemical vapor deposition reactor is formed from a plurality of elongated tubular elements extending side-by-side with one another in a plane transverse to the upstream to downstream direction of the reactor. The tubular elements have inlets for ejecting gas in the downstream direction. A wafer carrier rotates around an upstream to downstream axis. The gas distribution elements may provide a pattern of gas distribution which is asymmetrical with respect to a medial plane extending through the axis.

1 . A method of chemical vapor deposition comprising the steps of:
 (a) maintaining a wafer carrier holding one or more wafers within a reaction chamber so that surfaces of the wafers face in an upstream direction;   (b) rotating the wafer carrier around an axis extending in the upstream and downstream directions; and   (c) discharging a plurality of gasses downstream toward the wafer carrier from a plurality of elongated gas inlets extending parallel to one another in a first horizontal direction transverse to the axis, the discharging step being performed so that streams of first and second reactive gases are discharged from separate ones of the elongated inlets and so that a carrier gas carrier gas substantially devoid of the first and second reactive gasses and substantially nonreactive with the first and second reactive gasses is discharged from other ones of the reactive inlets and so that at least some of the streams of carrier gasses are discharged between adjacent streams of first and second carrier gasses.   
     
     
         2 . A method as claimed in  claim 1  wherein the first reactive gas includes one or more sources of one or more Group III metals and the second reactive gas includes and one or more sources of one or more Group V elements. 
     
     
         3 . A method of chemical vapor deposition comprising:
 (a) rotating a disc-like holder carrying the substrates about an axis while maintaining surfaces of the substrates substantially perpendicular to the axis and facing in an upstream direction along the axis; and, during the rotating step,   (b) discharging first and second gasses reactive with one another in a downstream direction parallel to the axis toward the substrates as first and second sets of gas streams extending to first and second radial distances from the axis, respectively, and simultaneously discharging a third gas substantially non-reactive with the first and second gases in the downstream direction as a third set of gas streams extending to a third radial distance from the axis greater than at least one of the first and second radial distances.