GaN Bulk Growth and Epitaxy from Ca-Ga-N Solutions

This SBIR proposal addresses the liquid phase epitaxy (LPE) of gallium nitride (GaN) films using nitrogen-enriched metal solutions. Growth of GaN from solutions offers the possibility of drastically reducing the density of line defects. As these defects adversely affect both breakdown voltages and electron velocities, their reduction can significantly increase the performance of high power Ka-band HEMT structures used for satellite communications. To achieve low defect densities in GaN films and efficient, large scale manufacturing, IIIAN will utilize new chemical growth methods based on nitrogen-enriched metal solutions, in particular the Ca-Ga-N ternary system. In the binary calcium-gallium alloy system it is possible to achieve a nitrogen atomic fraction of 2% at 900 oC and 2 bar. This is a significantly higher fraction than is possible in pure gallium solutions. For example, a temperature of ~1700 oC and pressure of ~10 kbar are necessary to achieve even 0.1% atomic nitrogen fraction in pure gallium solvent.