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Nanoscale platinum films are deposited by atomic layer deposition using trimethylmethylcyclopentadienyl-platinum and oxygen as precursors on the high-k dielectrics ZrO 2 and Al 2 O 3 , respectively, and on SiO 2 , issuing deposition temperature and precursor ratios. The ALD-grown platinum films are polycrystalline and show a preferential (1 1 1) orientation. The films are homogeneous with a root mean square roughness of 0.6-0.7 nm and reveal a low resistivity of 13.2 μ cm. The effective work functions are 4.76 eV for ZrO 2 , 5.22 eV for Al 2 O 3 and 5.52 eV for SiO 2 . It is remarkable that the deposition temperature of the platinum metal gate influences the final equivalent oxide thickness. Comparing both, PVD and ALD platinum films, a decreased leakage current density is observed for the ALD films depending on ALD process conditions, along with an increase in the equivalent oxide thickness.

In this work, we report on the fabrication, characterization, and photovoltaic properties of sputter-deposited, thin film heterojunctions combining p-type cupric oxide (CuO) absorber with n-type ZnO. The structural investigation reveals highly crystalline, columnar growth of the layers and confirms that the absorber's phase is purely CuO, with only negligible traces of Cu2O. The optical characterization yields for CuO an indirect bandgap of 1.2 eV and a direct optical transition at approximately 3 eV. The short circuit current, open circuit voltage, fill factor, and power conversion efficiency of the heterojunction solar cells were extracted as a function of the CuO thickness under AM1.5 G (1 kW/m2) illumination. From the observed dependencies, we conclude that the photovoltaic performance is compromised by a restricted carrier collection efficiency, caused by the small carrier lifetime in CuO. Indeed, the carrier population is found to decay with time constants of 40 and 460 ps. A maximum power conversion efficiency of 0.08% was obtained for the solar cell with CuO thickness of 500 nm.

We investigate ultrathin ZrO2/La2O3 high-k dielectric stacks on germanium grown by atomic layer deposition. La2O3 is deposited from tris(N,N′-diisopropylformamidinate)-lanthanum and oxygen. Interfacial layer-free oxide stacks with a relative dielectric constant of 21 and equivalent oxide thickness values as low as 0.5 nm are obtained. Metal oxide semiconductor capacitors with platinum as the gate electrode exhibit well-behaved capacitance-voltage characteristics, gate leakage current densities in the range of 0.01–1 A/cm2, and interface trap densities in the range of ∼3×1012 eV−1 cm−2.

We apply metal organic chemical vapour deposition (MOCVD) of HfO 2 and of ZrO 2 from β-diketonate precursors to grow high-k gate dielectrics for InAlN/AlN/GaN metal oxide semiconductor (MOS)-high electron mobility transistors (HEMTs). High-k oxides of about 12 nm-14 nm are deposited for the MOS-HEMTs incorporating Ni/Au gates, whereas as a reference, Ni-contact-based 'conventional' Schottky-barrier (SB)-HEMTs are processed. The processed dielectrics decrease the gate current leakage of the HEMTs by about four orders of magnitude if compared with the SB-gated HEMTs and show superior device characteristics in terms of I DS and breakdown.

We report on the improvement of electrical quality of (100)-Ge/high-k-dielectric interfaces by introducing thin Pt top layers on the dielectric and subsequent oxidative treatments or using a Pt-deposition process with inherent oxidative components. Here, deposition of thin physical vapor deposition-Pt layers, combined with subsequent oxygen treatments, or oxygen assisted atomic layer deposition of Pt on these dielectrics, is applied. Strong reduction of interface trap densities down to mid-1011 eV−1 cm−2 is achieved. The approach is shown for Pt/ZrO2/La2O3/Ge, Pt/ZrO2/GeO2/Ge, and Pt/ZrO2/Ge gate stacks. By x-ray photoelectron spectroscopy evidence is given for oxygen enrichment at Ge/high-k-dielectric interfaces, to be responsible for the improved electrical properties.

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