Atomic layer controlled deposition of SiO₂ and Al₂O₃ using ABAB... binary reaction sequence chemistry

Sequential ABAB... surface chemical reactions can be employed for atomic layer controlled deposition. We have examined the binary reactions SiCl₄+2H₂O{right semidirect product}SiO₂+4HCl for SiO₂ deposition and 2Al(CH₃)₃+3H₂O {right semidirect product} Al₂O₃+ 6CH₄ for Al₂O₃ deposition. Each binary reaction (A + B {right semidirect product} products) was performed sequentially by individual exposures to the A reactant and then the B reactant. If each surface reaction is self-limiting, repetitive ABAB... cycling may produce layer-by-layer controlled growth. For example, the individual "A" and "B" surface reactions for SiO₂ deposition can be described by (A) Si-OH + SiCl₄ {right semidirect product} Si-O-SiCl₃ + HCl, (B) Si-Cl + H₂O {right semidirect product} Si-OH + HCl. We have studied ABAB... binary reaction sequences for SiO₂ and Al₂O₃ deposition using laser-induced thermal desorption, temperature-programmed desorption and Auger electron spectroscopy techniques on single-crystal Si(100) surfaces. Fourier transform infrared spectroscopy techniques were also employed to examine these binary reaction schemes on high surface area SiO₂ and Al₂O₃ samples. Controlled deposition of SiO₂ and Al₂O₃ was demonstrated and optimized utilizing the above techniques. Under the appropriate conditions, each surface reaction was self-terminating and atomic layer controlled growth was a direct consequence of the binary reaction sequence chemistry.