Atomic layer controlled deposition of SiO 2 and Al 2O 3 using ABAB… binary reaction sequence chemistry

Abstract

Sequential ABAB… surface chemical reactions can be employed for atomic layer controlled deposition. We have examined the binary reactions SiCl 4+2H 2O⋌SiO 2+4HCl for SiO 2 deposition and 2Al(CH 3) 3+3H 2O ⋌ Al 2O 3+ 6CH 4 for Al 2O 3 deposition. Each binary reaction (A + B ⋌ 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 SiO 2 deposition can be described by (A) Si–OH + SiCl 4 ⋌ Si–O–SiCl 3 + HCl, (B) Si–Cl + H 2O ⋌ Si-OH + HCl. We have studied ABAB… binary reaction sequences for SiO 2 and Al 2O 3 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 SiO 2 and Al 2O 3 samples. Controlled deposition of SiO 2 and Al 2O 3 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.