Patent ID: 8101020

Claim:
A method for manufacturing a group III nitride crystal by using a crystal growth apparatus, said crystal growth apparatus comprising a crucible holding a melt mixture containing an alkali metal and a group III metal and a reaction vessel surrounding said crucible, said method comprising: a first step of loading said alkali metal and said group III metal into said crucible in an inert gas ambient or a nitrogen gas ambient; a second step of loading said alkali metal into a vessel space exposed to said melt mixture between said vessel space and an outside of said reaction vessel with an amount such that said alkali metal can exist between said vessel space and said outside in said inert gas ambient or nitrogen gas ambient at a temperature equal to or higher than a melting temperature of said alkali melt; a third step of filling said vessel space with a nitrogen source gas; a fourth step of heating said crucible and said reaction vessel to a crystal growth temperature; a fifth step of holding said crucible and said reaction vessel at said crystal growth temperature for a predetermined duration; and a sixth step of supplying said nitrogen source gas to said vessel space such that a pressure inside said vessel space is maintained to a predetermined pressure; wherein said second step is conducted so as to load said alkali metal between said crucible and said reaction vessel in said inert gas ambient or said nitrogen gas ambient with an amount such that said alkali metal can exist between said crucible and said reaction vessel at a temperature equal to or higher than said melting temperature of said alkali metal, wherein there is formed a first interface between said alkali metal melt, existing between said crucible and said reaction vessel, and the vessel space, and there is formed a second interface between said melt mixture and said vessel space, wherein said second step is conducted to load said alkali metal between said crucible and said reaction vessel with an amount such that said first interface generally coincides with said second interface at a temperature equal to or higher than said melting temperature of said alkali metal.