Quantitative Infrared Spectroscopy of Tetrakis(dimethylamido)Titanium for Process Measurements
| Autor: | James E. Maslar, Brent A. Sperling, William A. Kimes |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
chemistry.chemical_compound
Atomic layer deposition Materials science chemistry Vapor pressure Analytical chemistry Infrared spectroscopy Chemical vapor deposition Fourier transform infrared spectroscopy Spectroscopy Tetrakis(dimethylamido)titanium Electronic Optical and Magnetic Materials Group 2 organometallic chemistry |
| Zdroj: | ECS Journal of Solid State Science and Technology. 3:P26-P31 |
| ISSN: | 2162-8777 2162-8769 |
| DOI: | 10.1149/2.009403jss |
| Popis: | In situ infrared (IR) spectroscopy has proven to be an extremely valuable tool for understanding various aspects of chemical vapor deposition (CVD) and atomic layer deposition (ALD). Solid film deposits, gaseous precursors and by-products, and growth surfaces are all of interest in these processes, and IR spectroscopy is capable of providing useful data for each. Qualitative measurements are sometimes sufficient, but quantitative spectroscopy is often desired for work involving process monitoring or process development. Relating absorbancetoconcentrationscanbeproblematicforsurfacesandsolid deposits due to interactions, dielectric screening, etc., but measurements of the gas phase are straightforward if absorptivities are known. Efforts to obtain accurate IR reference spectra of CVD and ALD precursors, however, have been limited. 1 Commercial quantitative spectral libraries, if they include any precursors at all, typically contain only the most common ones (e.g., SiH4 and WF6). This is despite the use of IR spectroscopy for process monitoring in manufacturing 2 and for process development in the laboratory. 3,4 There is a need, therefore, for carefully obtained spectra of the less common precursors and for a general method of obtaining them. This work presents a static measurement for determining the IR absorptivities of low vapor pressure organometallic compounds used as precursors for CVD and ALD. We use Fourier transform IR (FTIR) spectroscopy to this end. Since the focus of this work is related to CVD and ALD processes where the compounds are typically heated to increase their vapor pressure, we obtain reference spectra at elevated temperatures. Heated samples are known to cause photometric errors in FT-IR spectroscopy, so we use a setup that is demonstrated to provide correct spectra. The apparatus and method for emission correction are discussed fully in the Experimental section. Quantitatively accurate IR spectra of tetrakis(dimethylamido)titanium (TDMAT), Ti[N(CH3)2]4 ,a re measured in the temperature range of (352 to 476) K. TDMAT is an alkylamido organometallic compound, a class of molecules that has found widespread use as CVD and ALD precursors in the semiconductor industry. TDMAT, in particular, is commonly used for the CVD of TiN and is under investigation for the ALD of TiO2. Qualitative IR spectra of TDMAT have been reported a number of times in the literature, 5‐11 which offers an opportunity to compare the results to previous studies and to elucidate the discrepancies. The temperature-dependent IR absorptivity is presented in the Results section, and a comparison to prior results can be found in the ∗ |
| Databáze: | OpenAIRE |
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