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The nitridation of vanadium films in molecular nitrogen and ammonia using a RTP‐system was investigated. The V films were deposited on silicon substrates covered by 100 nm thermal SiO2. For a few experiments sapphire substrates were used. Nitride formation at high temperatures (900 and 1100 °C) and interface reactions and diffusion of oxygen out of the SiO2‐layer into the metal lattice at moderate temperatures (600 and 700 °C) were studied. For characterisation complementary analytical methods were used: X‐ray diffraction (XRD) for phase analysis, secondary neutral mass spectrometry (SNMS) and Rutherford Backscattering (RBS) for acquisition of depth profiles of V, N, O, C and Si, transmission electron microscopy (TEM) in combination with electron energy filtering for imaging element distributions (EFTEM) and recording electron energy loss spectra (EELS) to obtain detailed information about the initial stages of nitride, oxide and oxynitride formation, respectively, and the microstructure and element distributions of the films. In these experiments the SiO2‐layer acts as diffusion barrier for nitrogen and source for oxygen causing the formation of substoichiometric vanadium oxides and oxynitrides near the V/SiO2‐interface primarily at temperatures ≤ 900 °C. At a temperature of 1100 °C just a small amount of oxynitride forms near the interface because rapid diffusion of nitrogen and fast formation of VN (diffusion barrier for oxygen) inhibit the outdiffusion of oxygen into the metal layer. In the 600 °C regime, in argon atmosphere oxynitride phases observed in the surface region of these films originate from reaction of residual oxygen in the argon gas, whereas NH3 as process gas does not lead to oxide or oxynitride formation at the surface (apart from the oxidation caused by storage). NH3 seems to support the diffusion of oxygen out of the SiO2‐layer. During the decomposition of ammonia at higher temperatures hydrogen is formed, which could attack the SiO2. In contrast, sapphire substrates do not act as oxygen source in the 600 °C regime and change the nitridation behaviour of the vanadium films.

B/Nb and B/Nb(2)N bilayers and Nb/B/Nb trilayers of about 550 nm total thickness have been deposited on Si(100) wafers with 100 nm thermally grown oxide. Nb and B layers were deposited by magnetron sputtering. Nb(2)N layers were prepared by nitridation of Nb films via rapid thermal processing (RTP). The samples were annealed subsequently at temperatures between 600 and 1,200 degrees C in an RTP system under Ar or NH(3) gas flow to study interdiffusion and reactivity of niobium, boron and nitrogen. Formation of phases was investigated by X-ray diffraction (XRD); surface morphology and roughness were studied via scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Elemental depth profiles of selected samples were recorded by secondary ion mass spectrometry (SIMS). Annealing of the B/Nb bilayers and Nb/B/Nb trilayers under Ar leads to the formation of Nb(3)B(2) at 1,200 degrees C at the B/Nb interface. At lower temperatures the high oxygen content in the boron layer is supposed to hinder the formation of borides due to formation of glass-like boron oxides. In NH(3) several niobium nitrides are formed but no boride phases. Here again the reactivity of boron with niobium is suppressed by the high oxygen content and boron oxide formation. During annealing of the B/Nb(2)N bilayers no borides were formed indicating that well-formed Nb(2)N is an effective diffusion barrier for B.

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CMOS-compatible thermopiles can be made by using the available polysilicon layer and aluminium layer as thermocouple. SiGe would however offer a better performance than silicon, mostly due to the much lower thermal conductivity [4], while it maintains CMOS compatibility. The figure of merit of a highly boron doped (about 1020 at/cm3) thin film poly-Si70%Ge30% layer deposited by ULPCVD is reported. The figure of merit is measured with a dedicated structure: the Seebeck coefficient is f 75 pV/K, the thermal conductivity is f 4.8 W/mK and the electrical resistivity is 2 3 p R m . The figure of merit is then calculated to be z = 50.10-6/K.