Multi-gas straight channel showerhead
A method and apparatus that may be utilized for chemical vapor deposition and/or hydride vapor phase epitaxial (HVPE) deposition are provided. In one embodiment, a metal organic chemical vapor deposition (MOCVD) process is used to deposit a Group III-nitride film on a plurality of substrates. A Group III precursor, such as trimethyl gallium, trimethyl aluminum or trimethyl indium and a nitrogen-containing precursor, such as ammonia, are delivered to a plurality of straight channels which isolate the precursor gases. The precursor gases are injected into mixing channels where the gases are mixed before entering a processing volume containing the substrates. Heat exchanging channels are provided for temperature control of the mixing channels to prevent undesirable condensation and reaction of the precursors.
1. A method for chemical vapor deposition using a showerhead, comprising:
flowing a first gas and second gas into a showerhead having:
a first plenum disposed within the showerhead;
a second plenum disposed within the showerhead;
a plurality of first gas flow channels formed within the showerhead and in fluid communication with the first plenum;
a plurality of second gas flow channels formed within the showerhead and in fluid communication with the second plenum, wherein the first plenum is disposed between the second plenum and the first and second gas flow channels;
a first plurality of gas conduits formed within the showerhead and coupling the first plenum to the first gas flow channels;
a second plurality of gas conduits formed within the showerhead and coupling the second plenum to the second gas flow channels;
a plurality of first gas injection holes formed within the showerhead and in fluid communication with the first gas flow channels; and
a plurality of second gas injection holes formed within the showerhead and in fluid communication with the second gas flow channels;
flowing the first gas into the first plenum and from the first plenum through the first plurality of gas conduits into the plurality of first gas flow channels; and
flowing the second gas into the second plenum and from the second plenum through the second plurality of gas conduits into the plurality of second gas flow channels.
2. The method of claim 1 , wherein the showerhead further has:
mixing channels formed in a surface of the showerhead and disposed downstream from the first and second gas injection holes for mixing the first gas and the second gas injected through the first and second gas injection holes.
3. The method of claim 1 , further comprising flowing a heat exchanging fluid through a heat exchanging channel formed in the showerhead.
4. The method of claim 1 , further comprising flowing a third gas into a plurality of third gas flow channels formed in the showerhead, wherein the first and second gases comprise precursor gases and the third gas comprises an inert gas.
5. The method of claim 1 , wherein the first and second gases comprise precursor gases and the first precursor gas comprises a Group III precursor and the second precursor gas comprises a Group V precursor.
6. The method of claim 5 , wherein the precursor gases have the general formula MX 3 and M includes one of gallium, aluminum or indium and X includes one of chlorine, bromine, or iodine.
7. The method of claim 5 , wherein the first and second precursor gases comprise plasma species.
8. The method of claim 1 , wherein the first gas is flowed through a plurality of first gas channels that are straight and parallel and the second gas is flowed through a plurality of second gas channels that are straight and parallel, and wherein the first gas channels and the second channels are parallel.
9. The method of claim 1 , further comprising:
flowing a fluid or plasma through a central conduit formed in the showerhead, wherein the central conduit is isolated from the plurality of first gas flow channels, the plurality of second gas flow channels, the first plenum, and the second plenum.