Effects of plasma shield plate design on epitaxial GaN films grown for large-sized wafers in radical-enhanced metalorganic chemical vapor deposition

Epitaxial growth of GaN films at a low temperature of 800 °C was studied in radical-enhanced metal-organic chemical vapor deposition, focusing on the discharge region of the plasma of a mixture of N2 and H2 gases. The effect of plasma confinement on the growth is crucial for realizing high crystal quality of grown GaN films, owing to the suppression of plasma-induced damage and decomposition of gallium precursors in the gaseous phase. By confined plasma in the discharge region using the plasma shield plates made of metal with multiple small holes effectively, GaN with a relatively flat surface was grown under conditions of higher V/III ratios. Epitaxial growth of GaN films was achieved by modifying the plate design and controlling the high V/III ratio using both the plasma-excitation power and the Ga precursor flow rate.