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The authors describe a remote plasma atomic layer deposition reactor (Oxford Instruments FlexAL™) that includes an inductively coupled plasma source and a load lock capable of handling substrates up to 200 mm in diameter. The deposition of titanium nitride (TiN) and hafnium oxide (HfO2) is described for the combination of the metal-halide precursor TiCl4 and H2–N2 plasma and the combination of the metallorganic precursor Hf[N(CH3)(C2H5)]4 and O2 plasma, respectively. The influence of the plasma exposure time and substrate temperature has been studied and compositional, structural, and electrical properties are reported. TiN films with a low Cl impurity content were obtained at 350 °C at a growth rate of 0.35 Å/cycle with an electrical resistivity as low as 150 μΩ cm. Carbon-free (detection limit <2 at. %) HfO2 films were obtained at a growth rate of 1.0 Å/cycle at 290 °C. The thickness and resisitivity nonuniformity was <5% for the TiN and the thickness uniformality was <2% for the HfO2 films as determined over 200 mm wafers. [ABSTRACT FROM AUTHOR]

The Maxwell–Wagner effect, the enhanced charge migration to the interface of a stack of two dielectrics with different conductances, is shown to cause asymmetric leakage current and electrical breakdown behavior for different electrode polarities. For this purpose, metal-insulator-silicon capacitors were fabricated consisting of bilayered silicon dioxide–lanthanum zirconate dielectric stacks. Maxwell–Wagner instability and Debye polarization can be distinguished upon comparing electron injection from both sides of the stack. The Maxwell–Wagner charges have relaxation times that are nearly five orders of magnitude larger than the Debye polarization, suggesting the long-lasting influence of these trapped charges in nanolaminated dielectric systems. [ABSTRACT FROM AUTHOR]

The use of aluminum as an electrode in metal-insulator-semiconductor devices containing lanthanum oxide is impaired by unacceptable leakage current levels. Time of flight secondary ion mass spectroscopy depth profiling shows a significant amount of silicon out-diffusion from the substrate and aluminum in-diffusion towards the oxide. By using titanium nitride as the electrode, the silicon out-diffusion is suppressed, which improves the device performance. This indicates that, despite the larger coordination number of the lanthanum ions in the oxide, aluminum acts as a sink for silicon, thus driving the out-diffusion of silicon. [ABSTRACT FROM AUTHOR]

The deposition of alternating (sub)monolayers of lanthanum oxide (La2O3) and zirconium oxide (ZrO2) by atomic layer deposition has been carried out to create uniform LayZr1-yOx mixed oxide films. However, spontaneous nucleation of ZrO2 nanocrystals occurs during deposition within an amorphous La2O3 matrix. Such ZrO2 embedded La2O3 films exhibit low leakage currents in combination with higher electric breakdown fields and higher dielectric permittivities than the pure lanthanum and zirconium oxide films. The possible scenarios that account for this enhanced electric performance of these nanocluster-embedded dielectric thin films are explained. [ABSTRACT FROM AUTHOR]