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This paper describes the fabrication of MOS capacitor and DLTS study of annihilation of deeplevel defects upon thermal annealing. Ni/SiO/ 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/SiO/ n-Si have been investigated using deep-level transient spectroscopy (DLTS). A characteristic deep-level defect at E = 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 ( E = 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. [ABSTRACT FROM AUTHOR]

Ni/SiO2/Si MOS structures were fabricated on n-type Si wafers and were irradiated with 50 MeV Li3+ ions with fluences ranging from 1×1010 to 1×1012 ions/cm2. High frequency C-V characteristics are studied in situ to estimate the build-up of fixed and oxide charges. The nature of the charge build-up with ion fluence is analyzed. Defect levels in bulk Si and its properties such as activation energy, capture cross-section, trap concentration and carrier lifetimes are studied using deep-level transient spectroscopy. Electron traps with energies ranging from 0.069 to 0.523 eV are observed in Li ion-irradiated devices. The dependence of series resistance, substrate doping and accumulation capacitance on Li ion fluence are clearly explained. The study of dielectric properties (tan δ and quality factor) confirms the degradation of the oxide layer to a greater extent due to ion irradiation. [ABSTRACT FROM AUTHOR]

Abstract: Commercial bipolar junction transistor (2N 2219A, npn) irradiated with 150MeV Cu11+-ions with fluence of the order 1012 ionscm−2, is studied for radiation induced gain degradation and deep level defects. I–V measurements are made to study the gain degradation as a function of ion fluence. The properties such as activation energy, trap concentration and capture cross-section of deep levels are studied by deep level transient spectroscopy (DLTS). Minority carrier trap levels with energies ranging from E C −0.164eV to E C −0.695eV are observed in the base–collector junction of the transistor. Majority carrier trap levels are also observed with energies ranging from E V +0.203eV to E V +0.526eV. The irradiated transistor is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 350°C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for transistor gain degradation. [Copyright &y& Elsevier]

Abstract: Commercial npn transistor (2N 2219A) irradiated with 50MeV Li3+-ions with fluences ranging from 3.1×1013 ionscm−2 to 12.5×1013 ionscm−2, is studied for radiation induced gain degradation and minority carrier trap levels or recombination centers. The properties such as activation energy, trap concentration and capture cross section of induced deep levels are studied by deep level transient spectroscopy (DLTS) technique. Minority carrier trap levels with energies ranging from 0.237eV to 0.591eV were observed in the base–collector junction of the transistor. In situ I–V measurements were made to study the gain degradation as a function of ion fluence. Ion induced energy levels result in increase in the base current through Shockley Read Hall (SRH) or multi-phonon recombination and subsequent transistor gain degradation. [Copyright &y& Elsevier]