• W S Khokle

      Articles written in Bulletin of Materials Science

    • Electrical and structural characteristics of oxides grown from polycrystalline silicon

      B B Dixit P D Vyas W S Khokle K Mahadevan H N Acharya

      More Details Abstract Fulltext PDF

      A comparative study of dielectric properties of polysilicon oxide with silicon dioxide, grown on single crystal silicon, shows that the former is more conducting due to the presence of asperites at polysilicon/SiO2 interface. This paper also reports attempts made to improve the electrical properties of polysilicon oxide by investigating the effects of oxidation temperature, polysilicon deposition temperature and doping on current field characteristics of polyoxide. Higher doping and higher oxidation temperature yield smoother interface with higher breakdown voltages and lower leakage currents. Surface morphology of polyoxide under different process conditions is also studied.

    • GaAs MESFET and related processes

      O P Daga J K Singh B R Singh H S Kothari W S Khokle

      More Details Abstract Fulltext PDF

      Since inception of GaAs MESFET in 1971, growth and processing technology of GaAs has matured to the extent that the analogue as well as digital IC production is persued at the industrial level. The ever increasing demand for higher frequency of operation, low noise figure and higher gain has led to newer device structures such as HEMT and HJBT based on GaAs and related compounds. Furthermore there exists exciting and proven capabilities in GaAs and related compounds to generate, detect and convert light into electrical signals. This has opened up vast field of opto-electronic devices and their integration with MESFET and other conventional devices.

      Basic building block of all these developmental activities still remains the GaAs MESFET, which have also been extensively used as low noise amplifiers, mixers, oscillators and high power amplifiers in descrete form. This paper reviews the design aspects, fabrication technology, d.c. and microwave characterization for both low noise and high power MESFET.

      Various technological advancements like via-hole for source grounding, air-bridge technology for low parasitic interconnects and polymide passivation, which have helped in further improvement in terms of higher frequency of operation, low noise and high power output are reviewed.

      Finally some representative results on the devices fabricated at CEERI are also presented.

    • On the measurement of microwave absorption of bulk YBaCuO superconductors in X-band (8–12 GHz)

      J K Singh H S Kothari O P Daga B R Singh W S Khokle

      More Details Abstract Fulltext PDF

      Microwave absorption at the surface of highTc YBaCUO superconducting sample has been determined in X-band by measuring VSWR. Power reflectivity >98% has been observed in the frequency range of 8·2–10·5 GHz indicating very low absorption at the surface. At some of the frequencies, however, negligible microwave loss has been observed.

  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

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