Epitaxial GaN using Ga(NMe2)3 and NH3 Plasma by Atomic Layer Deposition

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 substrates 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/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.