Ga-free AlInN films growth by close-coupled showerhead metalorganic chemical vapor deposition

In this paper, we have demonstrated that Ga-free AlInN can be obtained in the close-coupled showerhead (CCS) reactor metalorganic chemical vapor deposition (MOCVD) system when thorough cleaning was applied. For the AlInN films grown in the CCS reactor routinely used, the serious unintentional incorporation of gallium (Ga) atoms in AlInN was confirmed by the measurement results of secondary ion mass spectroscopy. To avoid the Ga incorporation, we removed the Ga-contained coatings on the surface of quartz liner, wafer susceptor, and showerhead. Then, in the reactor without Ga-contained coatings, Ga-free AlInN films were obtained. Moreover, the effect of growth parameters on the indium incorporation in AlInN and the structural properties of AlInN were studied systematically. It is worth noting that the realization of Ga-free AlInN in the CCS reactor is significantly important because CCS MOCVD system is widely used for the research and mass production of nitride materials and devices. • Demonstration of the epitaxial growth of Ga-free AlInN by CCS MOCVD. • Removing the Ga-contained coatings in CCS reactor is the key to achieve Ga-free AlInN. • Methods to control the indium content of AlInN is provided.