Crystalline Bi 2 S 3 nanorods, nanotapes, and nanocrystals were obtained from the solvent thermalysis of bismuth trisxanthate precursors and related bismuth dithiocarbamate species in ethylene glycol at 197 °C. Precursors with different structural motifs were designed to produce compounds with different thermal decomposition temparatures, i.e., the dimeric motif of Bi(S 2 COR) 3 when R ) methyl and ethyl was found to have a lower decomposition temperature compared to precursors adopting the polymeric structure, so that solvothermalysis of the former gave rise to short nanocrystals; while in the case of the latter, long nanofibers were produced instead. Chemical vapor deposition on silicon substrates yielded well-defined nanorods of various lengths and diameters for almost all precursors. Internal microstructure of the nanorods was studied by high-resolution transmission electron microscopy.

Metal-oxide-semiconductor capacitors were fabricated on germanium substrates by using metalorganic-chemical-vapor-deposited HfO2 as the dielectric and TaN as the metal gate electrode. It is demonstrated that a surface annealing step in NH3 ambient before the HfO2 deposition could result in significant improvement in both gate leakage current and the equivalent oxide thickness (EOT). It was possible to achieve a capacitor with an EOT of 10.5 Å and a leakage current of 5.02×10−5 A/cm2 at 1 V gate bias. X-ray photoelectron spectroscopy analysis indicates the formation of GeON during surface NH3 anneal. The presence of Ge was also detected within the HfO2 films. This may be due to Ge diffusion at the high temperature (∼400 °C) used in the chemical-vapor deposition process.

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Formation of Ge nanocrystals embedded in HfAlO high-k dielectric by co-sputtering of HfO2, Al2O3, and Ge, followed by rapid thermal annealing was demonstrated. Analysis by transmission electron microscopy and x-ray photoelectron spectroscopy confirmed the formation of nonoxidized Ge nanocrystals with a minimum size of about 5nm embedded in HfAlO dielectric. We also demonstrated the application of such nanocrystals in nonvolatile memory devices, achieving a 2.2V memory window as obtained from the C–V characterization of the memory device.

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