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The potential organic nonlinear optical material of hippuric acid (HA) single crystal has been grown by the slow evaporation solution growth technique usingN, N-dimethylformamide as the solvent. Single crystals of pure HA were irradiated at room temperature with 100 keV Nitrogen (N+) ions at fluence 1×1016and 5×1016ions/cm2. The pure and irradiated HA single crystals were characterized by different characterization technique. The photoluminescence and UV–visible absorption were performed at room temperature. The crystalline perfection of the pure and irradiated single crystals has been examined by high-resolution X-ray diffraction. Vickers microhardness technique was used to study the effect on the mechanical strength of the crystal at different ion fluences. The structural changes were analyzed by powder X-ray diffraction analysis. The functional groups of the synthesized compound have been identified by Fourier transform infrared spectroscopy. The dielectric constant and dielectric loss as a function of frequency were analyzed at room temperature. [ABSTRACT FROM PUBLISHER]

First-generation (50 GHz) silicon–germanium heterojunction bipolar transistors (SiGe HBT) were irradiated with 75 MeV boron ions and 100 MeV oxygen ions. The aim of the present investigation is to study the degradation of current–voltage (I–V) characteristics due to different linear energy transfer ions. Thein situ I–Vcharacteristics were measured before and after ion irradiation are forward mode and inverse mode Gummel characteristics, excess base current and current gain. It was found that the oxygen ion-irradiated SiGe HBT showed slightly more degradation when compared with boron ion-irradiated devices. The damage constant was calculated using the Messenger–Spratt equation, which confirmed more degradation in the case of oxygen ion-irradiated HBTs. [ABSTRACT FROM AUTHOR]

The total dose effects of 50 MeV lithium (Li3+) ions on 200 GHz (8HP) silicon-germanium heterojunction bipolar transistors (SiGe HBTs) are studied in total doses ranging from 300 krad to 10 Mrad. The different electrical characteristics, such as the Gummel characteristics, dc current gain (hFE), neutral base recombination, avalanche multiplication of carriers (M-1) and output characteristics (IC-VCE), were studied before and after Li3+ ion irradiation. The results of 50 MeV Li3+ ion irradiation on SiGe HBTs are compared with 60Co gamma irradiation results in the same dose ranges. [ABSTRACT FROM AUTHOR]

NPN transistors have been irradiated by 60 MeV oxygen ions in a fluence ranging from 5 × 1010 to 1 × 1013 ions/cm2. The DC current gain (hFE), excess base current (ΔIB=IB post−IB pre), excess collector current (ΔIC=IC post−IC pre) and collector saturation current (IC Sat) of the ion irradiated transistors were studied systematically. The hFE of the transistors were found to be decreased drastically after ion irradiation. A significant increase has been observed in the collector current (IC) along with the increase in the base current (IB) after ion irradiation. The IC Sat of the ion irradiated transistors were also decreased significantly after irradiation. The radiation induced trap levels in the collector base depletion region of NPN transistors were studied by deep level transient spectroscopy technique and different types of trap levels were observed. The results obtained on the activation energy, density of trap levels, apparent capture cross section, introduction rate and space charge layer lifetime of different defects for different total fluence are presented and discussed. [Copyright &y& Elsevier]

Abstract: The dc characteristics exhibited by NPN power transistors are studied systematically before and after irradiation by 100MeV F8+ ions and 50MeV Li3+ ions in the dose range of 100krad to 100Mrad. The transistor parameters such as excess base current (ΔI B=I Bpost–I Bpre), dc current gain (h FE), transconductance (g m), and collector-saturation current (I Csat) were studied before and after irradiation. The damage factors (k) for h FE were calculated for ion irradiated transistors using Messenger–Spratt relation. The base current (I B) was found to increase significantly after ion irradiation and this in turn decreases the h FE of the transistors. The g m decreases significantly after ion irradiation. Moreover, the output characteristics of irradiated devices also show that the collector current (I C) in the saturation region (I Csat) decrease with increase in ion dose. The observed change in these characteristics may be due to the ion induced generation–recombination (G–R) centers in emitter-base (E-B) spacer oxide and the ion induced point defects and their complexes in the transistor structure. [ABSTRACT FROM AUTHOR]

Abstract: N-channel MOSFETs were irradiated by 48MeV Li3+ ions, 100MeV F8+ ions and Co-60 gamma radiation with doses ranging from 100krad to 100Mrad. The threshold voltage (V TH), voltage shift due to interface trapped charge (ΔV Nit), voltage shift due to oxide trapped charge (ΔV Not), density of interface trapped charge (ΔN it), density of oxide trapped charge (ΔN ot), transconductance (g m), mobility (μ) of electrons in the channel and drain saturation current (I D Sat) were studied as a function of dose. Considerable increase in ΔN it and ΔN ot, and decrease in V TH, g m and I D Sat were observed in all the irradiated devices. We correlated the degradation of μ with the ΔN it and the effect of ΔN ot is found to be negligible for degrading the μ. The maximum degradation was observed for the devices irradiated with Co-60 gamma radiation when compared with those irradiated with ions, since gamma radiation can generate more trapped charge in field oxide when compared to the high energy ions. [Copyright &y& Elsevier]