In Situ Investigation of the Thermal Decomposition of Cl₄(CH₃CN)W(NⁱPr) During Simulated Chemical Vapor Deposition

Abstract

Design of precursors for thin film growth by chemical vapor deposition (CVD) can be informed by knowledge of the precursor decomposition mechanism. However, the vast majority of decomposition characterization is done by techniques that do not capture CVD conditions. This work used a custom CVD reactor with in situ Raman spectroscopy capabilities to investigate the gas phase thermal decomposition of the tungsten imido complex Cl4(CH3CN)WNiPr, a known precursor for the aerosol‐assisted (AA)CVD of tungsten carbonitride thin films. In combination with previous computational and ex situ data, we propose a decomposition mechanism for this precursor under CVD conditions, based on observation of gas phase products of N(imido)‐C bond homolysis and σ‐bond metathesis between the precursor W–Cl bond and H2.

An innovative GC-MS, NMR and ESR combined, gas-phase investigation during chemical vapor deposition of silicon oxynitrides films from tris(dimethylsilyl)amine

“…For example, in situ UV spectroscopic or FTIR exhaust gas studies have been used to establish chemical reactions paths in the CVD of gallium nitride (GaN) films, 21,22 and gas chromatography coupled with mass-spectrometry (GC-MS) was applied to investigate the thermal decomposition and by-products generation in CVD of titanium nitride (TiN) films. 23 More recent implementations involve in situ Raman spectroscopy during thermal decomposition of a tungsten imido complex by aerosol-assisted (AA)CVD, 24 or in situ optical emission spectroscopy during microwave plasma-enhanced chemical vapor deposition of phosphorus (P) and nitrogen (N) co-doped nanocrystalline diamond. 25 Focusing on analogous studies of CVD processes involving silicon-containing precursors, the majority of the reported 6 literature concerns the binary systems SiC, SiO2 or Si3N4 from chlorosilanes, silanes or TEOS.…”

Single-Source Precursors for the Chemical Vapor Deposition of Group 4–6 Transition Metal Dichalcogenides

“…Examples of such mechanistic studies are presented in this Perspective. It is also important to obtain data during deposition using techniques such as RGA of reactor effluent or in situ spectroscopy of gas-phase species generated from simulated or real CVD. , …”

“…It is also important to obtain data during deposition using techniques such as RGA of reactor effluent or in situ spectroscopy of gas-phase species generated from simulated or real CVD. 100,101 Traditional CVD remains a standard technique for synthesizing high-quality conformal thin films for numerous applications, but the requirement of precursor volatility for traditional CVD imposes a limitation on the precursors that can be used. AACVD offers the advantage of avoiding the volatility requirement, which allows for greater freedom in designing precursors.…”