Structures, kinetics, and energetics of reactive intermediates in hot-wire chemical vapor deposition of Si-containing films

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The research program involves the studies of kinetics, structures and energetics of gas-phase reactive intermediates formed in the hot-wire chemical vapor deposition (HWCVD) process of Si-containing semiconductor thin films. It also involves the application of the scientific findings from gas phase studies to optimize the film formation process. The gas phase reactive species are the major source of film growth precursors in HWCVD. They are particularly important in determining the film growth rate and film properties. In our research, laser-based ionization techniques, such as vacuum ultraviolet laser single photon ionization (SPI) and laser-induced electron impact ionization (LIEI), will be used in tandem with time-of-flight mass spectrometry (TOF MS) to identify the reactive species and to understand the chemical kinetics that produce precursor species for film growth. We will also utilize several laser spectroscopic techniques, including resonance-enhanced multiphoton ionization (REMPI), zero kinetic energy (ZEKE) photoelectron / mass analyzed threshold ionization (MATI) spectroscopy, to characterize the rovibronic structures of the excited neutrals and ground state cations, and to determine the accurate ionization energies of the reactive intermediates. The research will lead to the development of highly sensitive and selective diagnostic tools for these species. It will also provide fundamental properties of the reactive intermediates, which are extremely difficult to obtain, yet invaluable in the study of radical-radical and radical-molecule reactions. Finally, we will employ various surface diagnostic methods to examine the properties of the thin films produced at various deposition conditions to achieve general design parameters for HWCVD equipment. Together, this research will contribute to a deep molecular level understanding of the fundamental chemistry and physics involved in the HWCVD processes. This knowledge is essential to develop a comprehensive deposition model and to provide important guidance toward rational optimization of film formation in HWCVD to obtain superior quality films for industrial applications.