Thin films of niobium nitride are useful for their physical, chemical, and electrical properties. NbN superconducting properties have been utilized in a wide range of applications. Plasma-enhanced atomic layer deposition (PEALD) of NbN with (t-butylimido) tris(diethylamido) niobium(V) and remote H2/N2 plasmas has been investigated. Deposited film properties have been studied as a function of substrate temperature (100–300 °C), plasma power (150–300 W), and H2 flow rate (10–80 sccm). PEALD NbN films were characterized with spectroscopic ellipsometry (thickness, optical properties), four point probe (resistivity), x-ray photoelectron spectroscopy (composition), x-ray reflectivity (density and thickness), x-ray diffraction (crystallinity), and superconductivity measurements. Film composition varied with deposition conditions, but larger cubic NbN crystallites and increased film density at higher substrate temperatures and H2 flow rates lead to room temperature resistivity values as low as 173 μΩ cm and superconductivity critical temperatures as high as 13.7 K.

We present in situ topographical observations of film growth during the initial cycles of atomic layer deposition (ALD) using scanning tunneling microscopy (STM). We present cycle-by-cycle STM topographs of zinc sulfide films during ALD on Au(111) surfaces, tracking individual grains, 5 nm in diameter, as they grow over tens of cycles. We find that grain morphology is temperature-dependent and grain size increases with deposition temperature from 100 to 160 °C.

Tungsten nitride (WN) has potential as an interconnect barrier film. Deposition of WN films with bis(tert-butylimido)bis(dimethylamido)tungsten utilizing plasma-enhanced atomic layer deposition has been investigated over a temperature range of 100–400 °C employing N2, H2/N2, and NH3 remote plasmas. Spectroscopic ellipsometry has been used to determine film thickness and optical properties. Film growth rate varied from 0.44 to 0.65 Å/cycle. Chemical composition was investigated with x-ray photoelectron spectroscopy. W:N ratios varied from 0.95:1 to 3.76:1 and carbon levels were sub-2% for atomic layer deposition conditions. Resistivity measurements, derived from four-point probe measurements, indicate higher deposition temperature and gas flow rates produce the lowest resistivity films. The lowest resistivity film of the study, which measured 405 μΩ cm, was deposited with a hydrogen-rich H2/N2 plasma at 400 °C.

NbTiN has a variety of superconducting applications, ranging from RF cavities to single-photon detectors. Here, we systematically investigated the plasma-enhanced atomic layer deposition (PEALD) of NbxTi with the organometallic precursors (t-butylimido) tris(diethyamido) niobium(V) and tetrakis (dimethylamido) titanium in conjunction with a remote H2/N2 plasma. Deposited film properties have been studied as a function of the ratio of Nb to Ti precursor pulses within each ALD supercycle. PEALD NbTiN films were characterized with spectroscopic ellipsometry (thickness, optical properties), four point probe (resistivity), x-ray photoelectron spectroscopy (composition), x-ray reflectivity (density and thickness), x-ray diffraction (crystallinity), and superconductivity measurements. The PEALD process has shown distinct advantages over deposition of superconducting films via thermal ALD or sputtering, for example a lower processing temperature and more efficient control of film composition. This control of film composition enabled the tuning of electrical and superconducting properties, such as varying the superconducting critical temperature TC between 6.9 and 13.2 K.

We study the nucleation stage and growth of atomic layer deposition (ALD) on hydrogen terminated silicon (Si:H) by in situ and ex situ scanning tunneling microscopy (STM). STM allows the in-depth study of surface chemistry and evolution during the ALD nucleation phase. Here, the ALD systems studied to demonstrate this technique are ZnO via diethyl zinc (DEZ) and TiO 2 via titanium tetrachloride (TiCl 4 ). In-situ STM revealed that DEZ does not discriminate between different surface sites, in contrast to TiCl 4 which shows a strong preference toward dangling or OH bonds. Continued deposition showed distinct island growth for TiO 2 deposition on Si:H, versus homogeneous growth for DEZ. ZnO ALD exhibited a delay of approximately 5 ALD cycles in transitioning from lateral to vertical growth and nominal physical film closure occurred after approximately 12−15 cycles. STM observations of these ALD chemistries demonstrated the strength of this technique in quantifying film closure and the effects of surface termination and defects on ALD growth mode. This technique can be applied to the study of a broad variety of ALD systems.