• Mukesh Kumar

      Articles written in Bulletin of Materials Science

    • Electron microscopic studies of thermomechanically aged 2218 aluminium alloy

      Mukesh Kumar S Singh D B Goel

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      The effect of thermomechanical ageing (TMA) treatment on the microstructure and mechanical properties of 2218 Al alloy has been studied. This was followed by hardness measurements and transmission electron metallography (TEM). The 2218 Al alloy was given various thermomechanical ageing treatments including partial peak ageing, warm rolling and further ageing to peak hardness level. Without thermomechanical treatment the peak hardness value was 130 VHN. With thermomechanical treatment there was an overall improvement in hardness. This is attributed to the combined effect of dislocation precipitate networks and the fineness ofθ′ particles.

    • Thin films of Y-Ba-Cu-O by rf sputtering and study of Josephson effect

      Mukesh Kumar N D Kataria V S Tomar V N Ojha N Khare S U M Rao G S N Reddy A K Gupta

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      Thin films of Y-Ba-Cu-O material have been prepared by rf diode sputtering using a single oxide target on strontium titanate substrates kept at an ambient temperature. It was found difficult to attain stoichiometry of the films identical to that of the target due to resputtering of the films. The influence of sputtering parameters such as target-substrate distance, rf power, gas pressure and substrate temperature in attaining a particular stoichiometry of the film has been studied. The I–V characteristics of the bridges show Shapiro steps when the bridges are irradiated with microwave radiations. The thin film bridges have the dimensions larger than coherence length; thus all the Josephson effect features are understood to arise due to intergranular junctions.

    • Semiconductor applications of plasma immersion ion implantation technology

      Mukesh Kumar Rajkumar Dinesh Kumar P J George

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      Many semiconductor integrated circuit manufacturing processes require high dose of implantation at very low energies. Conventional beam line ion implantation system suffers from low beam current at low energies, therefore, cannot be used economically for high dose applications. Plasma immersion ion implantation (PIII) is emerging as a potential technique for such implantations. This method offers high dose rate irrespective of implantation energy. In the present study nitrogen ions were implanted using PIII in order to modify the properties of silicon and some refractory metal films. Oxidation behaviour of silicon was observed for different implantation doses. Diffusion barrier properties of refractory barrier metals were studied for copper metallization.

    • Estimation of scattering from a moist rough surface with spheroidal dust particles

      Mukesh Kumar

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      The scattering from moisture rough surface with spheroidal dust particles having surface with spheroidal dust particles has recently received much attention. In part due to the recent prediction and observation of the spheroidal dust particles in rough surfaces under elastic wave by the Kirchhoff scattering model and scalar approximation with slope. Our analysis shows that the scattering depends on the moisture (2–4.5%) with spheroidal dust particles. At slightly moisture rough surface the dielectric properties increase with change in field amplitude in a rough surface with spheroidal dust particles.

    • Effect of thin Mo2C layer on thermal stability of Si/SiO2/Ti/Cu system

      C C Tripathi Mukesh Kumar Dinesh Kumar

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      The effect of introducing a thin Mo2C (30 nm) layer between Ti and Cu on the thermal stability of Si/SiO2/Ti/Cu system was studied using four-point probe (FPP), scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDAX) and X-ray diffraction (XRD) techniques. The measured value of the sheet resistance in the bi-layered diffusion barrier structure does not show any change up to an annealing temperature of 750°C. The sheet resistance when measured after annealing at 800°C marginally increases but less than twice its value at room temperature. The XRD analysis indicated no copper diffusion and the formation of Cu3Si phase up to 800°C. The bi-layered barrier structure annealed at elevated temperature shows copper-depleted and agglomerated regions. The sheet resistance measurement, study of surface morphology and the XRD analysis confirm that the insertion of thin Mo2C layer increases the thermal stability of the system from 400°C to 750°C. The increased thermal stability of the system is ascribed to longer diffusion path length in the bi-layered system probably because of grain boundaries mismatch at Ti–Mo2C interface.

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