Group III nitride photonic devices on silicon carbide substrates with conductive buffer interlay structure

An optoelectronic device with a Group III Nitride active layer, said device comprising:

• a conductive silicon carbide substrate;
• an ohmic contact to said substrate;
• an optoelectronic diode with a Group III nitride active layer;
• a buffer structure selected from the group consisting of gallium nitride and indium gallium nitride between said silicon carbide substrate and said optoelectronic diode;
• and
• a stress-absorbing structure comprising a predetermined grid pattern of grooves in the surface of said silicon carbide substrate and a corresponding grid pattern of stress-absorbing areas propagated into said buffer from said grooves in said substrate, so that stress-induced cracking that occurs in said buffer structure occurs at said predetermined areas rather than elsewhere in said buffer structure.