Silicon carbide crystal growth in a CVD reactor using chlorinated chemistry
A silicon carbide growth method for growing a silicon carbide crystal on a substrate in a hot wall reaction chamber heated to a temperature between 1600° C. and 2000° C. Process gases enter the reaction chamber utilizing at least a primary gas flow, a secondary gas flow, and a shower gas flow. The shower gas flow is fed substantially perpendicularly to the primary and secondary gas flows and is directed towards the substrate. The primary and secondary gas flows are oriented substantially parallel to the surface of the substrate. A silicon precursor gas is entered by the primary gas flow. A hydrocarbon precursor gas is entered in at least one of the primary gas flow, the secondary gas flow, or the shower gas flow. Hydrogen is entered primarily in the secondary flow and the shower head flow. A CVD reactor chamber for use in processing the method.
1. A silicon carbide growth method for growing a silicon carbide crystal on a substrate in a hot wall reaction chamber, wherein the reaction chamber is heated to a temperature in the region 1600° C. to 2000° C., the method comprising:
entering process gases into the reaction chamber by use of at least three gas flows, a primary gas flow, a secondary gas flow surrounding the primary gas flow, and a shower gas flow, wherein said primary and secondary gas flows stream substantially parallel to the surface of the substrate, and where the shower gas flow is fed substantially perpendicularly to the primary and the secondary gas flows and being directed towards the substrate,
a chlorine containing silicon precursor gas is entered into the reaction chamber utilizing the primary gas flow together with a carrier gas,
a hydrocarbon precursor gas is entered into the reaction chamber according to at least one of the following alternatives:
together with the chlorine containing silicon precursor gas and a flow ratio x of hydrogen in the primary flow,
together with a flow ratio y of hydrogen, in the secondary flow,
together with a flow ratio z of hydrogen in the shower head flow,
wherein the flow ratio of hydrogen is in the relation x<y<z;
according to all alternatives hydrogen is entered into the reaction chamber in the secondary gas flow at a flow ratio y, and in the shower gas flow at a flow ratio z, wherein y<z.
2. The method according to claim 1 , wherein an etch gas is entered into the reaction chamber utilizing an etch gas flow introduced at the substrate holder.
3. The method according to claim 1 , wherein the chlorine containing silicon precursor gas is silicon tetrachloride, SiCl 4 , trichlorosilane HSiCl 3 , a chlorosilane, or a methyltrichlorosilane.
4. The method according to claim 1 , wherein the hydrocarbon is at least one of ethylene, C 2 H 4 , C 2 H 2 , CH 4 , C 3 H 8 , C 2 H 6 , or CH 3 Cl.
5. The method according to claim 1 , wherein the secondary flow is 3 to 50 times the flow of the chlorine containing silicon precursor flow, and the shower head flow is 1 to 20 times the chlorine containing silicon precursor flow.
6. The method according to claim 1 , wherein the hydrogen flow part of the main flow including the primary flow and secondary flow is between 1 and 10 times the chlorine containing silicon precursor flow.
7. The method according to claim 1 , wherein the pressure inside the reaction chamber is kept at a pressure between 50 mbar and 1000 mbar, between 75 mbar and 600 mbar, or between 100 mbar and 400 mbar.
8. The method according to claim 1 , wherein the C/Si ratio of total flow into the reaction chamber is between 0.3 and 1.5, between 0.5 and 1.2, or between 0.7 and 1.0.
9. The method according to claim 1 , wherein the Si/H 2 total flow ratio is between 0.1% and 10%, and the H 2 /Ar total flow ratio is between 1 and 50.
10. The method according to claim 1 , wherein the Cl/Si ratio is between 2 and 10 or between 3 and 5.
11. The method according to claim 2 , wherein the etch gas is HCl or a mix of HCl and H 2 .
12. The method according to claim 1 wherein Ar is added as a part of the secondary flow.
13. The method according to claim 1 , wherein an amount of HCl is added to the primary gas flow.