Atomic Layer Deposition as the Enabler for the Metastable Semiconductor InN and Its Alloys

Indium nitride (InN) is a low-band-gap semiconductor with unusually high electron mobility, making it suitable for IR-range optoelectronics and high-frequency transistors. However, the development of InN-based electronics is hampered by the metastable nature of InN. The decomposition temperature of InN is lower than the required growth temperature for most crystal growth techniques. Here, we discuss growth of InN films and epitaxial layers by atomic layer deposition (ALD), a growth technique based on self-limiting surface chemical reactions and, thus, inherently a low-temperature technique. We describe the current state of the art in ALD of InN and InN-based ternary alloys with GaN and AlN, and we contrast this to other growth technologies for these materials. We believe that ALD will be the enabling technology for realizing the promise of InN-based electronics.