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Abstract Chemical Vapour Deposition (CVD) of cobalt was deposited from a liquid source precursor of cobalt tricarbonyl nitrosyl (Co(CO)3NO) on to oxidised < 100 > silicon wafers. The cobalt layers were deposited at 450∘C at 1.5 torr chamber pressure of hydrogen for 15 min processing time with various precursor flow rates. X-ray diffraction studies of the cobalt films reveal both hcp and fcc peaks. The vibrating sample magnetometer (VSM) yields coercivity (Hc) 167 Oe and 364 Oe for 46 nm and 30 nm thickness layers respectively at room temperature and squareness (S) Mr/Ms (remanence/saturation of magnetisation) value of  1. The study of magnetic properties of the cobalt suggests that magnetisation is dependent on grain size and therefore thickness. The grain size was observed by atomic force microscopy (AFM). Magnetic images were observed by magnetic force microscopy (MFM) and analyzed in terms of domain structure. The surface domain structure was recorded with the tip lift height 100 nm so that the magnetic interactions arising produced the topography effect. Where there is repulsive interaction the intensity is recorded as a bright region and where the interaction is attractive the intensity is recorded as a dark region. [ABSTRACT FROM AUTHOR]

Abstract Chemical vapour deposition (CVD) of copper on titanium-coated substrates was performed in a stainless steel reactor using copper(I) hexafluoroacetylacetonate trimethylvinylsilane (Cu(I)hfac(TMVS)) as a precursor and nitrogen (N2) as carrier gas. Film resistivity, film composition and surface morphology were studied in relation to deposition temperature, process pressure and process gas flow ratio. The lowest resistivity value obtained was around 2 μΩcm. In addition, cross-sectional examination of the copper films, using a LEO SEM imaging system, indicated increased film porosity at higher deposition temperatures. An optimum carrier gas flow rate was determined: higher carrier gas flow rates caused excessive dilution of the copper precursor, whilst lower carrier gas flow rates weakened the transport of the copper precursor to the substrate. XRD data revealed formation of copper oxide (Cu2O) if annealing temperatures exceeded 450∘C for a period of 30 min. [ABSTRACT FROM AUTHOR]

Abstract Spiral inductors were fabricated in copper to take advantage of its low resistivity. The single-layered square inductors, with number of turns varying from 2 to 7, were contacted by underpasses. The measured inductances were in the range of 2.8 to 8.5 nH. Inductances, quality factors, resonance frequencies, series resistances and substrate capacitances were extracted from the measured S-parameters. The performance of different inductor geometries was studied. Varying track width affects both the inductance and the resonance frequencies. Wires with smaller cross-section area have a slightly larger inductance because they generate more magnetic flux external to the wire. Varying track spacing also had an effect on the inductor performance due to cross-talk signals caused by the close proximity of the tracks. To improve the Q performance of the inductors, the thickness of the underlying SOG dielectric layers (? = 3) was increased from 0.8 to 2 µm. Acceptable Q values of 9.5 to 12 were obtained at a frequency of 1.3 GHz. Insertion of a blanket ground plane below the dielectric caused the Q values to drop dramatically due to eddy currents formed in the ground plane. In order to break up the formation of these eddy currents, perforated ground shields were employed. This technique proved successful and Q factors were almost restored to their original values. [ABSTRACT FROM AUTHOR]

Tungsten and tungsten nitride layers have been deposited by plasma-enhanced chemical vapor deposition (PECVD). Tungsten layers deposited at low deposition temperatures T~150 °C using this method showed good uniformity over dielectric and silicon substrate areas. As the deposition temperature decreased, the silicon consumed during the deposition reaction decreased, at T~150 °C no silicon consumption was measurable. PECVD tungsten nitride layers were deposited directly on oxidized silicon substrates with no requirement for a nucleation layer. As the NH3 flow rate was increased, whilst maintaining all other parameters constant, deposited layers were found to change from metal tungsten to tungsten-rich amorphous layer to W2N. The resistivity of the layers was found to be high compared to published literature for higher-temperature deposited layers. The high resistivity is attributed to the incorporation of fluorine into the layer at low deposition temperatures. A deposition process was established for smooth amorphous tungsten-rich WxN layers at 150 °C. [ABSTRACT FROM AUTHOR]