Method for manufacturing a group III-nitride crystal comprising supplying a group III-element oxide gas and a nitrogen element-containing gas at a supersaturation ratio of greater than 1 and equal to or less than 5
A method of manufacturing a group-III nitride crystal includes: preparing a seed substrate; and supplying a group-III element oxide gas and a nitrogen element-containing gas at a supersaturation ratio (P o /P e ) greater than 1 and equal to or less than 5, then, growing a group-III nitride crystal on the seed substrate, wherein the P o is a supply partial pressure of the group-III element oxide gas, and the P e is an equilibrium partial pressure of the group-III element oxide gas.
1. A method of manufacturing a group-III nitride crystal comprising:
preparing a seed substrate; and
supplying a group-III element oxide gas and a nitrogen element-containing gas at a supersaturation ratio (P o /P e ) greater than 1 and equal to or less than 5, then, growing a group-III nitride crystal on the seed substrate,
wherein the P o is a supply partial pressure of the group-III element oxide gas,
the P o is higher than or equal to 0.0004 atm and lower than or equal to 0.0076 atm,
the P e is an equilibrium partial pressure of the group-III element oxide gas such that a first reaction and a second reaction are in equilibrium,
in the first reaction, the group-III nitride crystal is generated from the group-III element oxide gas and the nitrogen element-containing gas, and
in the second reaction, a group-III element gas is generated from decomposition reaction of the group-III element oxidation gas.
2. The method of manufacturing a group-III nitride crystal according to claim 1 , wherein in the step of supplying the group-III element oxide gas and the nitrogen element-containing gas, the group-III element oxide gas and the nitrogen element-containing gas are supplied from a temperature lower than a substrate temperature of the growing step to introduce a group-III nitride crystal decomposition suppression layer.
3. The method of manufacturing a group-III nitride crystal according to claim 1 , wherein in the step of supplying the group-III element oxide gas and the nitrogen element-containing gas, the supersaturation ratio (P o /P e ) is set to equal to or greater than 1.3 and less than 2.5.
4. The method of manufacturing a group-III nitride crystal according to claim 1 , wherein in the step of supplying the group-III element oxide gas and the nitrogen element-containing gas, the supersaturation ratio (P o /P e ) is set to equal to or greater than 1.3 and less than 2.5, and
the group-III element oxide gas and the nitrogen element-containing gas are supplied from a substrate temperature of the seed substrate of 1050° C. or less to introduce a group-III nitride crystal decomposition suppression layer.
5. The method of manufacturing a group-III nitride crystal according to claim 1 , wherein in the step of supplying the group-III element oxide gas and the nitrogen element-containing gas, the nitrogen element-containing gas is higher than or equal to 0.030 atm and lower than or equal to 0.0444 atm.
6. The method of manufacturing a group-III nitride crystal according to claim 1 , wherein in the step of supplying the group-III element oxide gas and the nitrogen element-containing gas, the growth rate of the group-III nitride crystal is higher than or equal to 32 μm/h and lower than or equal to 61 μm/h.