Low temperature deposition of high-quality epitaxial GaN is crucial for its integration in electronic applications. Chemical vapor deposition at approximately 800 °C using SiC with an AlN buffer layer or nitridized sapphire as substrate is used to facilitate the GaN growth. Here, we present a low temperature atomic layer deposition (ALD) process using tris(dimethylamido)gallium(iii) with NH3 plasma. The ALD process shows self-limiting behaviour between 130-250 °C with a growth rate of 1.4 Å per cycle. The GaN films produced were crystalline on Si (100) at all deposition temperatures with a near stochiometric Ga/N ratio with low carbon and oxygen impurities. When GaN was deposited on 4H-SiC, the films grew epitaxially without the need for an AlN buffer layer, which has never been reported before. The bandgap of the GaN films was measured to be ∼3.42 eV and the Fermi level showed that the GaN was unintentionally n-type doped. This study shows the potential of ALD for GaN-based electronic devices.

Journal of Materials Chemistry C
Department of Chemistry

Rouf, P. (Polla), O'Brien, N.J. (Nathan J.), Buttera, S.C. (Sydney C.), Martinovic, I. (Ivan), Bakhit, B. (Babak), Martinsson, E. (Erik), … Pedersen, H. (Henrik). (2020). Epitaxial GaN using Ga(NMe2)3and NH3plasma by atomic layer deposition. Journal of Materials Chemistry C, 8(25), 8457–8465. doi:10.1039/d0tc02085k