Derivatives (Scheme1). TH(PSNa) 8 was synthesized by the following procedure. To a suspension of NaH (95%, 1.76 g, 70.1 mmols) in anhydrous DMSO was added dropwise trehalose (2.5 g, 7.3 mmols) through a dropping funnel under nitrogen with magnetic stirring. The reaction mixture was heated at 50 o C for 2 hr. Into the suspension 1,3-propansultone (10.0 g, 82.0 mmols) was added dropwise. The reaction mixture was heated at 50 o C for 12 hr. and 80 o C for 12 hr. The mixture was cooled to room temperature and filtered through a fritted filter to remove any precipitate. An ethanol/water mixture (9/1) was added slowly with stirring to cause precipitation. The solid was collected, washed with a mixture of ethanol/water (9/1), and dried at 50 o C under vacuum. The product was purified further by precipitation from DMF/Water (6/1), washing with DMF, and drying under vacuum. Finally, the product was stirred in boiling methanol for 1hr., filtered and dried under vacuum at 60 o C to give 5.9 g of the desired product in 54% yield. 1 H NMR (500MHz, DMSO-d 6 ) δ 4.

Hafnium oxide films have been deposited on silicon substrates by metal organic chemical vapor deposition using the novel single precursor, hafnium 3-methyl-3-pentoxide {Hf[OC(CH3)(C2H5)2]4, Hf(mp)4}, with no additional oxygen source, and the deposition mechanism was elucidated. Hf(mp)4 is a liquid at room temperature and has a moderate vapor pressure comparable to that of hafnium tert-butoxide, Hf(OtBu)4, and a lower residual weight (<10%) in thermogravimetric analysis. The deposition rate was found to be ∼27 Å/min at 400 °C, and the activation energy was 68.1 kJ/mol, which is higher than those of other hafnium alkoxide and hafnium amide precursors. By gas chromatography/mass spectroscopy and nuclear magnetic resonance analyses of the thermally decomposed vapor phase products collected during the deposition of HfO2 films, it was clearly found that they are grown via β-hydrogen elimination processes of the Hf(mp)4 single precursor. Negligible carbon incorporation of the HfO2 films, examined by X-ray photoelectron spectroscopy and depth-profiling Auger electron spectroscopy, indicates that, except for the β-hydrogen elimination processes, no additional decomposition and/or recombination processes contributed to the HfO2 film growth. The morphology, crystallinity, and electrical properties of the HfO2 films were characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction, and capacitance−voltage and current−voltage measurements.