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 °C and negligible residual mass. Strikingly, two temperature intervals with selflimiting 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 °C had a sheet resistivity of 920 Ω/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.

Indium nitride (InN) is an interesting material for future high frequency electronics, due to its high electron mobility. The problematic deposition of InN films currently prevents full exploration of InN based electronics. We present studies of atomic layer deposition (ALD) of InN using In precursors with bidentate ligands forming In-N bonds; tris(N,N-dimethyl-N',N''diisoproprylguanidinato)indium(III), tris(N,N'-diisopropylamidinato)indium(III) and tris(N,N'-diisopropylformamidinato)indium(III). These compounds form a series were the size of the substituent in the endocyclic position decreases from -NMe2, to -Me and to -H, respectively. We show that when the size of the substituent decreases, InN films with higher crystallinity and optical quality, lower roughness and an In/N ratio closer to unity is achieved.From quantum chemical calculations we show that the smaller substituents lead to less steric repulsion and weaker bonds between the ligand and In centre. We propose that these effects render a more favoured surface chemistry for the nitridation step in the ALD cycle which explains the improved film properties.

Gallium nitride (GaN) is the main component of modern-day high electron mobility transistor electronic devices due to its favorable electronic properties. As electronic devices become smaller with more complex architecture, the ability to deposit high-quality GaN films at low temperature is required. Herein, we report a new highly volatile Ga(III) triazenide precursor and demonstrate its ability to deposit high-quality epitaxial GaN by atomic layer deposition (ALD). This new Ga(III) triazenide precursor, the first hexacoordinated M–N bonded Ga(III) precursor used in a vapor deposition process, was easily synthesized and purified by sublimation. Thermogravimetric analysis showed single step volatilization with an onset temperature of 150 °C and negligible residual mass. Three temperature intervals with self-limiting growth were observed when depositing GaN films. In the second growth interval, the films were found to be near stoichiometric with very low levels of impurities and epitaxial orientation on 4H-SiC without an AlN seed layer. The films grown at 350 °C were found to be smooth with a sharp interface between the substrate and film. The bandgap of these films was 3.41 eV with the Fermi level at 1.90 eV, showing that the GaN films were unintentionally <i>n</i>-type doped. This new triazenide precursor enables ALD of GaN for semiconductor applications and provides a new Ga(III) precursor for future deposition processes.

Gallium nitride (GaN) is the main component of modern-day high electron mobility transistors due to its favorable electronic properties. As electronic devices become smaller with more complex surface architecture, the ability to deposit high-quality GaN films at low temperatures is required. Herein, we report a new highly volatile Ga(III) triazenide precursor and demonstrate its ability to deposit high-quality epitaxial GaN by atomic layer deposition (ALD). This new Ga(III) triazenide, the first hexacoordinated Ga−N bonded precursor used in a vapor deposition process, was easily synthesized and purified by either sublimation or recrystallisation. Thermogravimetric analysis showed single-step volatilization with an onset temperature of 155 °C and negligible residual mass. Three temperature intervals with self-limiting growth were observed when depositing GaN films. The GaN films grown in the second growth interval at 350 °C were epitaxial on 4H−SiC without an AlN seed layer and found to have a near stoichiometric Ga/N ratio with very low levels of impurities. In addition, electron microstructure analysis showed a smooth film surface and a sharp interface between the substrate and film. The band gap of these films was 3.41 eV with the Fermi level at 1.90 eV, showing that the GaN films were unintentionally n-type-doped. This new triazenide precursor enables ALD of GaN for semiconductor applications and provides a new Ga(III) precursor for future deposition processes.

Only a few M–N bonded divalent group 14 precursors are available for vapor deposition, in particular for Ge and Pb. A majority of the reported precursors are dicoordinated with the Sn(II) amidinates, the only tetracoordinated examples. No Ge(II) and Pb(II) amidinates suitable for vapor deposition have been demonstrated. Herein, we present tetracoordinated Ge(II), Sn(II), and Pb(II) complexes bearing two sets of chelating 1,3-di- tert -butyltriazenide ligands. These compounds are thermally stable, sublime quantitatively between 60 and 75 °C (at 0.5 mbar), and show ideal single-step volatilization by thermogravimetric analysis.