- Institutionen för molekylära vetenskaper, Sveriges lantbruksuniversitet
In Situ Activation of an Indium(III) Triazenide Precursor for Epitaxial Growth of Indium Nitride by Atomic Layer Deposition
O'Brien, Nathan J.; Rouf, Polla; Samii, Rouzbeh; Ronnby, Karl; Buttera, Sydney C.; Hsu, Chih-Wei; Ivanov, Ivan G.; Kessler, Vadim; Ojamae, Lars; Pedersen, Henrik
Indium nitride (InN) is characterized by its high electron mobility, making it a ground-breaking material for high frequency electronics. The difficulty of depositing high-quality crystalline InN currently impedes its broad implementation in electronic devices. Herein, we report a new highly volatile In(III) triazenide precursor and demonstrate its ability to deposit high-quality epitaxial hexagonal InN by atomic layer deposition (ALD). The new In(III) precursor, the first example of a homoleptic triazenide used in a vapor deposition process, was easily synthesized and purified by sublimation. Thermogravimetric analysis showed single step volatilization with an onset temperature of 145 degrees C and negligible residual mass. Strikingly, two temperature intervals with self-limiting growth were observed when depositing InN films. In the high-temperature interval, the precursor underwent a gas-phase thermal decomposition inside the ALD reaction chamber to produce a more reactive In(III) compound while retaining self-limiting growth behavior. Density functional theory calculations revealed a unique two-step decomposition process, which liberates three molecules of each propene and N-2 to give a smaller tricoordinated In(III) species. Stoichiometric InN films with very low levels of impurities were grown epitaxially on 4H-SiC. The InN films deposited at 325 degrees C had a sheet resistivity of 920 Omega/sq. This new triazenide precursor enables ALD of InN for semiconductor applications and provides a new family of M-N bonded precursors for future deposition processes.
Chemistry of Materials
2020, Volym: 32, nummer: 11, sidor: 4481-4489
Utgivare: AMER CHEMICAL SOC
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