The preparation and the properties of titanium dioxide (TiO2) thin films have been studied with respect to its application as a new capacitor dielectric material in low-power high-density dynamic random access memory ultralarge scale integrated circuits. The TiO2 films were deposited by a low pressure metal organic chemical vapor deposition process with tetra-iso-propyltitanate as the precursor metal organic material. The deposition was performed in a hot wall-type vertical furnace at low temperatures (300-350~Very uniform TiO2 thin films with a dielectric constant up to 70 were prepared showing the polycrystalline structure of anatase after the deposition. The electronic properties of the TiO2-silicon interface were investigated in detail using a metal-insulator-semiconductor structure. Stoichiometry, structure, as well as electrical properties of the TiO2 layers were examined before and after an annealing treatment in oxygen ambient.

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For the first time successful application of thin boron oxide films grown by atomic layer deposition (ALD) as dopant source for shallow silicon doping is presented. ALD of B2O3 was carried out using tris(dimethylamido)borane and ozone as precursors. A growth per cycle of 0.3 Aå was obtained for 50 °C deposition temperature. Pure B2O3 films were highly instable after exposure to air but could be protected by thin Sb2O5 films that were in-situ grown by ALD as well. Rapid thermal annealing resulted in high concentration of active boron close to the silicon surface. The dependence of the doping results on the thickness of the initial B2O3 films could be shown and the favourable capping properties of the Sb2O5 material, which is chemically very stable in the as-deposited state but volatile and hence self-destructive at the annealing temperatures, were demonstrated.

Radio frequency plasma power dependence of the moisture permeation barrier characteristics of Al2O3 films deposited by remote plasma atomic layer deposition Comparison between ZnO films grown by plasma-assisted atomic layer deposition using H2O plasma and O2 plasma as oxidant J. Vac. Sci. Technol. A 31, 01A142 (2013); 10.1116/1.4771666Substrate-biasing during plasma-assisted atomic layer deposition to tailor metal-oxide thin film growth J. Vac. Sci. Technol. A 31, 01A106 (2013); 10.1116/1.4756906Reaction mechanisms during plasma-assisted atomic layer deposition of metal oxides: A case study for Al 2 O 3Plasma-assisted atomic layer deposition (PALD) was carried for growing thin boron oxide films onto silicon aiming at the formation of dopant sources for shallow boron doping of silicon by rapid thermal annealing (RTA). A remote capacitively coupled plasma source powered by GaN microwave oscillators was used for generating oxygen plasma in the PALD process with tris(dimethylamido)borane as boron containing precursor. ALD type growth was obtained; growth per cycle was highest with 0.13 nm at room temperature and decreased with higher temperature. The as-deposited films were highly unstable in ambient air and could be protected by capping with in-situ PALD grown antimony oxide films. After 16 weeks of storage in air, degradation of the film stack was observed in an electron microscope. The instability of the boron oxide, caused by moisture uptake, suggests the application of this film for testing moisture barrier properties of capping materials particularly for those grown by ALD. Boron doping of silicon was demonstrated using the uncapped PALD B 2 O 3 films for RTA processes without exposing them to air. The boron concentration in the silicon could be varied depending on the source layer thickness for very thin films, which favors the application of ALD for semiconductor doping processes.

This work reports on the dielectric strength of oxide layers formed by thermal oxidation of silicon carbide (SiC). SiC epilayers grown homoepitaxially on the silicon face of 6H-SiC and 4H-SiC substrates were oxidized in dry or wet ambient at 1100 °C. The dielectric strength was investigated using metal–oxide-semiconductor capacitors and was found to be tightly bound to 10 MV/cm for oxide thicknesses around 65 nm and independent of the SiC polytype and substrate doping. Considering the current-voltage characteristics in the prebreakdown region, dry oxides exhibit superior quality. Fowler–Nordheim tunneling was identified as the limiting current mechanism in the dry oxides. The corresponding barrier heights between the two SiC polytypes and thermal silicon dioxide were determined.

Silver (Ag) layers were deposited by remote plasma enhanced atomic layer deposition (PALD) using Ag(fod)(PEt3) (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluorooctane-3,5-dionato) as precursor and hydrogen plasma on silicon substrate covered with thin films of SiO2, TiN, Ti/TiN, Co, Ni, and W at different deposition temperatures from 70  to 200 °C. The deposited silver films were analyzed by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive x-ray spectroscopy, four point probe measurement, ellipsometric measurement, x-ray fluorescence (XRF), and x-ray diffraction (XRD). XPS revealed pure Ag with carbon and oxygen contamination close to the detection limit after 30 s argon sputtering for depositions made at 120 and 200 °C substrate temperatures. However, an oxygen contamination was detected in the Ag film deposited at 70 °C after 12 s argon sputtering. A resistivity of 5.7 × 10−6 Ω cm was obtained for approximately 97 nm Ag film on SiO2/Si substrate. The thickness was determined from the SEM cross section on the SiO2/Si substrate and also compared with XRF measurements. Polycrystalline cubic Ag reflections were identified from XRD for PALD Ag films deposited at 120 and 200 °C. Compared to W surface, where poor adhesion of the films was found, Co, Ni, TiN, Ti/TiN and SiO2 surfaces had better adhesion for silver films as revealed by SEM, TEM, and AFM images.

Thin films of BiO X , Sr X Ta Y O Z , and strontium bismuth tantalate (SBT) were deposited by metal-organic (MO)CVD on 150 mm silicon (100) wafers. Some of the wafers were pre-deposited with Pt electrodes. The substrate temperature and the deposition pressure were varied from 300 C to 600 C and from 0.35 mbar to 7 mbar, respectively. Bi(CH 2 CH=CH 2 ) 3 (triallylbismuth) and Sr[Ta(OEt) 5 (OC 2 H 4 OMe)] 2 (strontium-bis[tantalum(pentaethoxide)(2-methoxyethoxide)]) were used as Bi precursor and as Sr-Ta precursor, respectively. A liquid delivery system was used to supply and to vaporize the precursors into the reactor. X-ray photoelectron spectroscopy (XPS) and ellipsometry were carried out to characterize the film properties. The growth rate of the MOCVD of BiO X and Sr X Ta Y O Z was compared to the growth rate of SBT to obtain information about mutual interaction between the precursors. The deposition rate of bismuth oxide thin films was low (~10 nm h ±1 at 0.35 mbar) and virtually independent of the temperature. On the contrary, the growth rate of strontium tantalate films depended strongly on the temperature. The deposition rate of the SBT films was similar to the bismuth oxide film deposition, which slightly increased with increasing substrate temperature. However, the deposition rate of SBT was always lower than deposition rate of the single precursors. The growth rate significantly depended on pressure. The decrease of the deposition pressure in the reactor chamber reduced the deposition rate of BiO X , Sr X Ta Y O Z , and SBT but on the other hand, it improved the uniformity of the film thickness. XPS measurements showed a deficit of bismuth in the SBT films even though the concentration of the Bi precursor had been several times higher than the concentration of Sr-Ta precursor. The XPS depth-profiling by Ar + ion sputtering indicated more metallic bond characteristics of Ti, Sr, and Bi after ion-beam bombardment.