Diethyldiethoxysilane as a New Precursor for SiO2 Growth on Silicon

Abstract

AbstractDiethyldiethoxysilane (DEDEOS) is a potential single molecular precursor for SiO2 growth. Additionally, DEDEOS may be applicable in a deposition scheme that will allow precise atomic layer control of SiO2 film thicknesses. Deposition of SiO2 on silicon using DEDEOS was studied in three regimes. In the first regime, the adsorption and decomposition of DEDEOS were studied using temperature-programmed desorption (TPD) and Fourier-transform infrared spectroscopy (FTIR) under UHV conditions. TPD and FTIR results indicated that DEDEOS deposits ethyl and ethoxy species on the surface which decompose by a β-hydride elimination mechanism. In the second regime, step-wise SiO2 growth using DEDEOS was studied by laser-induced thermal desorption (LITD) and TPD as a function of repetitive growth cycles composed of DEDEOS deposition at 300 K followed by thermal annealing to 820 K. The amount of SiO2 growth per cycle initially decreased as a function of cycle until reaching a constant value after approximately 10 cycles. Finally, DEDEOS deposition of SiO2 was studied in a high pressure chamber at surface temperatures between 873 K and 1003 K and at a pressure of 0.5 Torr. The deposition of SiO2 as a function of exposure was found to display a fast initial growth step followed by a slower step which continued indefinitely. The activation energy for SiO2 growth by DEDEOS in the slower growth step was found to be 49 ± 6 kcal/mol. This activation energy is very similar to the activation energy of 45 kcal/mol observed for SiO2 growth by tetraethoxysilane (TEOS).