Large-Area MOCVD Growth of Ga 2 O 3 in a Rotating Disc Reactor

Gallium oxide is a wide-bandgap semiconductor material which is being developed for a range of electronic and electrooptic device applications. Commercial implementation of these devices will require production-scale technology for Ga 2 O 3 film deposition. This work demonstrated deposition of uniform Ga 2 O 3 films on both 50-mm-diameter (0001) sapphire and 200-mm-diameter (100) silicon substrates, using a rotating disc metalorganic chemical vapor deposition reactor. The source reactants were trimethylgallium and oxygen. The resulting Ga 2 O 3 films were smooth, optically transparent, and highly insulating and had excellent thickness uniformity. Ga 2 O 3 films deposited on (0001) sapphire at temperatures of at least 600°C and pressures of at least 45 Torr consisted of ( 2 0 1 )-oriented β-Ga 2 O 3 in the as-deposited state. The β-crystal structure was shown to be stable on annealing to 800°C, in either air or nitrogen atmosphere. A Ga 2 O 3 film deposited at a lower temperature was shown to crystallize to a similar ( 2 0 1 )-oriented β-Ga 2 O 3 structure on postdeposition annealing at 800°C.