Growth of epitaxial GaN on LiGaO2 substrates via a reaction with ammonia

Oriented GaN and LixGa(2-x)O2N2(1-x) thin films were found to grow on LiGaO 2 single-crystal (001) substrates via a reaction between ammonia (or reacti ve ammonia species) and substrate components at temperatures between 700 an d 1000 degreesC. The compound LixGa(2-x)O2xN2(1-x), where x was determined to be approximate to0.35, is a solid solution formed from a partial reactio n of ammonia with the LiGaO2 substrate. Negligible lithium (i.e., x approxi mate to 0) was detected in the films formed with a constant high flow rate (164 cm(3)/min) of ammonia, indicating a complete reaction with the LiGaO2 single crystal. The growth of a partial surface film and surface pitting su ggests a vapor reaction (via loss of LINH2 or LiOH, and nitridation of Ga2O ) similar to that observed when semiconductor grade reacts with Nz to form Si3N4. The resultant films have either a wurtzite structure or one approach ing the wurtzite structure. Both films form on the substrate with the same orientation as the LiGaO2.