• R Damle

      Articles written in Bulletin of Materials Science

    • High-energy heavy ion testing of VLSI devices for single event upsets and latch up

      S B Umesh S R Kulkarni R Sandhya G R Joshi R Damle M Ravindra

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      Several very large scale integrated (VLSI) devices which are not available in radiation hardened version are still required to be used in spacecraft systems. Thus these components need to be tested for highenergy heavy ion irradiation to find out their tolerance and suitability in specific space applications. This paper describes the high-energy heavy ion radiation testing of VLSI devices for single event upset (SEU) and single event latch up (SEL). The experimental set up employed to produce low flux of heavy ions viz. silicon (Si), and silver (Ag), for studying single event effects (SEE) is briefly described. The heavy ion testing of a few VLSI devices is performed in the general purpose scattering chamber of the Pelletron facility, available at Nuclear Science Centre, New Delhi. The test results with respect to SEU and SEL are discussed.

    • Study of effect of composition, irradiation and quenching on ionic conductivity in (PEG)𝑥 : NH4NO3 solid polymer electrolyte

      R Damle P N Kulkarni S V Bhat

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      We have prepared, characterized and investigated a new PEG-2000 based solid polymer electrolyte (PEG)𝑥: NH4NO3. Ionic conductivity measurements have been made as a function of salt concentration as well as temperature in the range 265–330 K. Selected compositions of the electrolyte are exposed to a beam of 8 MeV electrons and 60Co 𝛾-rays to an accumulated dose of 10 kGy to study the effect on ionic conductivity. The electrolyte samples are also quenched at liquid nitrogen temperature and conductivity measurements are carried out. The ionic conductivity at room temperature exhibits a characteristic peak for the composition, 𝑥 = 46. Electron beam irradiation results in an increase in conductivity for all compositions by a factor of 2–3. Exposure to 𝛾-rays enhances the conductivity by one order of magnitude. Quenching at low temperature has resulted in an increase in conductivity by 1–2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is interpreted as due to an increase in amorphous region and decrease in crystallinity of the electrolyte. DSC and NMR measurements also support this conclusion.

    • DLTS study of annihilation of oxidation induced deep-level defects in Ni/SiO2/𝑛-Si MOS structures

      N Shashank Sanjeev K Gupta K V Madhu J Akhtar R Damle

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      This paper describes the fabrication of MOS capacitor and DLTS study of annihilation of deeplevel defects upon thermal annealing. Ni/SiO2/𝑛-Si MOS structures fabricated on 𝑛-type Si wafers were investigated for process-induced deep-level defects. The deep-level traps in Si substrates induced during the processing of Ni/SiO2/𝑛-Si have been investigated using deep-level transient spectroscopy (DLTS). A characteristic deep-level defect at 𝐸C = 0.49 eV which was introduced during high-temperature thermal oxidation process was detected. The trap position was found to shift to different energy levels (𝐸C = 0.43, 0.46 and 0.34 eV) during thermal annealing process. The deep-level trap completely anneals at 350°C. Significant reduction in trap density with an increase in recombination life time and substrate doping concentration as a function of isochronal annealing were observed.

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