Yttrium oxide films are deposited on silicon using a new precursor, tris͑ethylcyclopentadienyl͒ yttrium with water vapor as the oxidizer, by means of atomic layer deposition ͑ALD͒. Film growth kinetics has been examined under different reactor conditions, and growth saturation is evident from precursor dosage dependence. The film thickness increases linearly with the number of deposition cycles, yielding a growth rate of 1.7 Ϯ 0.1 Å/cycle at optimal ALD conditions. Increasing the reactor temperature from 200 to 400°C shows gradual increase in growth rate, with a narrow temperature plateau in the range of 250-285°C. X-ray photoelectron spectral analysis of Y 2 O 3 films indicates the film to be stoichiometric with no evidence of carbon contamination, whereas glancing incidence X-ray diffraction data of as-deposited Y 2 O 3 suggests the film structure to be polycrystalline.

Tetrakis ͑diethylamino͒ hafnium ͑TDEAH͒, tetrakis ͑diethylamino͒ titanium ͑TDEAT͒, and H 2 O were used for the atomic layer deposition ͑ALD͒ of HfO 2 , TiO 2 , and Hf x Ti 1−x O 2 films on silicon substrates. The ALD temperature windows were found to be 175-250°C for HfO 2 ͑0.12 nm/cycle͒ and 150-250°C for TiO 2 ͑ ϳ0.06 nm/cycle͒. The 175-250°C overlap region is ideal for the ALD of the Hf x Ti 1−x O 2 films. Different compositions of Hf x Ti 1−x O 2 were obtained by varying the ͓TDEAH/H 2 O͔/͓TDEAT/H 2 O͔ cycle ratios, and excellent tunability of film composition was found using X-ray photoelectron spectroscopy ͑XPS͒. The Hf x Ti 1−x O 2 deposition rate was found to be the superposition of the two individual growth rates. Both as-deposited and postdeposition annealed films were studied with XPS, phase shift interferometry, and grazing incidence X-ray diffraction. As-deposited HfO 2 and TiO 2 films were found to be amorphous, and they began to crystallize after annealing at 600°C in the monoclinic phase ͑HfO 2 ͒ and in weak anatase phase ͑TiO 2 ͒. The Hf x Ti 1−x O 2 films remained amorphous after annealing up to about 1000°C in N 2 for 5 min.Structural and interfacial studies of ultrathin, high dielectric constant ͑͒ films during high temperature fabrication processes are critical to the continuous scaling of microelectronic devices. In particular, these materials are of great importance for the gate insulator of metal oxide semiconductor field effect transistors and the capacitor dielectric of dynamic random access memories. 1,2 So far, many candidate materials such as have been studied for the replacement of SiO 2 . 3 From all these materials, HfO 2 and TiO 2 seem to be promising candidates due to their favorable properties. HfO 2 is known to have relatively good thermal stability and compatibility with the Si substrate, and it has a dielectric constant of 15-30 with a large bandgap ͑5.7 eV͒. 4-6 TiO 2 is even more favorable in terms of its dielectric constant which is 80 or higher; 7 however, it has a rather small bandgap ͑3.1 eV͒, 8 which could result in more leakage current than that of HfO 2 . The reported crystallization temperature of each of these two materials has been reported to be as low as ϳ550°C. 9,10The earliest atomic layer deposition ͑ALD͒ of HfO 2 from tetrakis ͑diethylamino͒ hafnium ͑TDEAH͒ and H 2 O was published by Deshpande et al. with a growth rate of ϳ0.13 nm/cycle at 300°C. 11 Titanium tetrachloride ͑TiCl 4 ͒ and titanium isopropoxide ͑TTIP͒ have typically been used as metal precursors in the ALD of TiO 2 films, with water being the oxidant. 12-16 Growth rates of 0.03 nm/cycle or lower in these systems were reported. Our earlier ALD studies with other homoleptic metal precursors having the diethylamino ligand, such as TDEAH and tris ͑diethylamino͒ aluminum, have resulted in broad ALD temperature windows and rather high growth rates. 9,11,17,18 Such results have prompted interest in examining the suitability of tetrakis ͑diethylamino͒ titanium ͑TDEAT͒ as a precursor for the ALD of TiO 2 ...

Atomic layer deposition of hafnium oxide from tetrakis (diethylamino) hafnium (TDEAH) and water vapor was employed to create thin films on silicon with reactor temperatures as low as 30o C. Spectral ellipsometry and X-ray photoelectron spectroscopy were used to probe the thickness and composition of these films. Deposition at the same temperature of 30o C was carried out on poly-caprolactone (PCL) nanofibers as a template to examine the possibility of fabricating hafnium oxide nanotubes. Energy dispersive X-ray scans and scanning electron microscope images revealed significant hafnia coverage on the fibers, suggesting that hafnium oxide nanotubes can be formed by means of polymer vaporization after deposition.

Ultra-thin films of Al2O3 were deposited on Si(100) by atomic layer deposition (ALD) using tris(diethylamino)aluminium (TDEAA) with water vapor as the oxidizer. It is planned to deposit nano-laminated composite films of HfxTi1-xO2 on top of this ultra-thin Al2O3 buffer layer using tetrakis(diethylamino)titanium (TDEAT) and tetrakis(diethylamino)hafnium (TDEAH). The introduction of the Al2O3 buffer layer will improve the interfacial quality and help to retain amorphous structure of HfxTi1-xO2/Al2O3/Si. Discussion of the addition of the new precursor, TDEAA, to the existing ALD system is discussed along with the optimization of process parameters for ALD of Al2O3 films. An Al2O3 film growth rate of 1 cycle was achieved in the ALD temperature window of 200-275o C.