Method of epitaxially growing device structures with submicron group III nitride layers utilizing HVPE

A method of epitaxially growing a Group III nitride semiconductor device in a single epitaxial growth run, the method utilizing HVPE techniques and comprising the steps of:

• locating a first gallium (Ga) source in a source boat within a first source zone of an HVPE reactor, said first Ga source having a first exposed surface area;
• locating a second Ga source in a quartz channel within a second source zone of said HVPE reactor, said Ga source having a second exposed surface area, wherein said second exposed surface area is less than said first exposed area;
• locating a substrate within a growth zone of said HVPE reactor, wherein said growth zone is maintained at a first temperature;
• heating said first Ga source to a second temperature;
• heating said second Ga source to a third temperature;
• introducing a halide reaction gas into said first source zone to form a first gallium chloride compound;
• transporting said first gallium chloride compound to said growth zone;
• transporting a reaction gas to said growth zone, said reaction gas containing nitrogen (N);
• reacting said first gallium chloride compound with said reaction gas to achieve a first epitaxial growth rate of greater than 0.1 microns per hour;
• growing a first Group III nitride layer to a thickness of greater than 5 microns;
• transferring said substrate to a growth interruption zone maintained at a fourth temperature, wherein said fourth temperature is within 50° C. of said first temperature;
• directing an inert gas in a flow direction that substantially prevents said first gallium chloride compound and said reaction gas from entering said growth interruption zone;
• purging said growth zone;
• introducing said halide reaction gas into said second source zone to form a second gallium chloride compound;
• transporting said second gallium chloride compound to said growth zone;
• reacting said second gallium chloride compound with said reaction gas to achieve a second epitaxial growth rate of less than 0.1 microns per hour;
• and
• growing a second Group III nitride layer to a thickness of less than 0.02 microns.