Device-quality copper and nickel films were deposited onto planar and etched silicon substrates by the reduction of soluble organometallic compounds with hydrogen in a supercritical carbon dioxide solution. Exceptional step coverage on complex surfaces and complete filling of high-aspect-ratio features of less than 100 nanometers width were achieved. Nickel was deposited at 60°C by the reduction of bis(cyclopentadienyl)nickel and copper was deposited from either copper(I) or copper(II) compounds onto the native oxide of silicon or metal nitrides with seed layers at temperatures up to 200°C and directly on each surface at temperatures above 250°C. The latter approach provides a single-step means for achieving high-aspect-ratio feature fill necessary for copper interconnect structures in future generations of integrated circuits.

Ce_1 − xZr_xO₂ solid solutions are produced continuously by hydrolysis of mixtures of cerium ammonium nitrate and zirconium acetate in near-critical water at ca. 300 °C and 25 MPa using a flow reactor. Rapid hydrothermal coprecipitation leads to nano-particulate Ce_1 − xZr_xO₂ (x = 0–1), the composition of which is largely determined by the initial relative concentrations of Ce⁴⁺ and Zr⁴⁺ ions in the starting solution. The freshly prepared materials are crystalline, possess very small particle sizes, and have high surface areas. The effects of calcining the products in air at high temperature have been studied. Apart from the 1∶1 Ce∶Zr solid solution, the phases of Ce_1 − xZr_xO₂ remain stable on calcining to 1000 °C, but the particles sinter and the surface areas decrease significantly. The materials have been characterised by Powder X-ray Diffraction (PXD), IR and Raman Spectroscopy, microanalysis, Thermogravimetric Analysis (TGA), X-ray Fluorescence (XRF) and BET (surface area measurements). In selected cases, high resolution Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images were recorded to examine the particle morphology.

Magnetic spinel type oxides such as magnetite, Fe₃O₄, cobalt, nickel, and zinc ferrites, MFe₂O₄ (M = Co, Ni, Zn) and the mixed nickel and cobalt ferrite, Ni_xCo_1 − xFe₂O₄ have been synthesised continuously by the hydrolysis and simultaneous oxidation of mixtures of Fe(II) acetate and different M(II) acetates in near-critical and supercritical water using a flow reactor. The materials have been characterised by powder X-ray diffraction (PXD) and, in selected cases, by transmission electron microscopy (TEM). The bulk composition of the samples was determined by Atomic Absorption analysis (AA). Additionally, Energy-dispersive Detection X-ray analysis (EDX) was carried out on some of the samples. TEM pictures showed a “bimodal” particle size distribution: small particles of ca. 10 nm and larger particles of up to 100 nm, both of which are highly crystalline. Possible reaction mechanisms are discussed, which may be responsible for the observed morphology. The effects of temperature and residence time on the reaction have been studied.