Tapered Horizontal Growth Chamber
A system and techniques for performing deposition having a tapered horizontal growth chamber which includes a susceptor and a tapered channel flow block. A tapered chamber is formed between the susceptor and the tapered channel flow block. Gaseous species introduced are forced by the tapered channel block to flow toward the susceptor to enhance the efficiency of reactions between the gases species and a wafer on the susceptor.
1 . An MOCVD apparatus comprising:
an inlet region;
an outlet region;
a susceptor region between the inlet region and the outlet region; and
a flow region tapering from a first dimension at the inlet region to a second smaller dimension at the outlet region.
2 . The apparatus of claim 1 further comprising a heater coupled to the susceptor region.
3 . The apparatus of claim 1 further comprising cooling channels positioned near the flow region.
4 . The apparatus of claim 1 wherein the inlet region includes cooling channels.
5 . The apparatus of claim 1 further comprising a shower head dispenser configured to dispense into the flow region.
6 . An apparatus for epitaxial growth comprising:
a reactor housing;
a susceptor having a holding surface for holding a wafer;
a tapered flow block, the tapered flow block having a tapered surface facing the holding surface;
a chamber formed between the holding surface and the tapered surface, the chamber being characterized a first height at a first end and a second height at a second end, the first height being defined by a first distance between the tapered surface and the holding surface at the first end, the second height being defined by a second distance between the tapered surface and the holding surface at the second end, the first height being greater than the second height by at least 20%;
a nozzle for introducing gaseous species into the chamber; and
a heating module thermally coupled to the susceptor.
7 . The apparatus of claim 6 wherein the tapered flow block comprises metal and includes a showerhead assembly for dispensing cooling fluid.
8 . The apparatus of claim 6 wherein the susceptor is capable of rotation.
9 . The apparatus of claim 8 further comprising an airfoil positioned near the susceptor to cause the susceptor to rotate.
10 . The apparatus of claim 6 wherein the nozzle comprises a plurality of vertically stacked flow channels.
11 . The apparatus of claim 6 wherein the nozzle comprises a plurality of flow channels placed side-by-side.
12 . The apparatus of claim 6 wherein the tapered surface is substantially flat.
13 . The apparatus of claim 6 wherein the first height is at about 2 mm to 20 mm and the second height is about 0.5 mm to 5 mm.
14 . The apparatus of claim 6 wherein the susceptor comprises a wafer backing plate configured to rotate at a predetermined rate.
15 . The apparatus of claim 6 wherein the gaseous species comprise NH3, MO, H2, and N2.
16 . The apparatus of claim 6 further comprising:
a shower head positioned within the tapered flow block and having a substantially circular shape and a plurality of circular flow channels; and
an optical viewport located on the shower head.
17 . The apparatus of claim 16 wherein the susceptor is positioned below the tapered flow block.
18 . The apparatus of claim 16 wherein the susceptor is positioned above the tapered flow block.
19 . An apparatus for epitaxial growth comprising:
a reactor housing;
a susceptor having a holding surface for holding a wafer;
a tapered flow block having a tapered surface facing the holding surface;
a chamber between the holding surface and the tapered surface, the chamber being characterized a first height at a first end and a second height at a second end, the first height being defined by a first distance between the tapered surface and the holding surface at the first end, the second height being defined by a second distance between the tapered surface and the holding surface at the second end, the first height being different from the first height by at least 20%; and
a nozzle for introducing gaseous species into the chamber.
20 . The apparatus of claim 19 further comprising a heating module positioned around the susceptor.