We have developed a doping technique using broad ion beam below 10 keV without mass seperation by an apparatus consisting of a substrate chamber and an ion source with RF (13.56MHz) electric field and magnetic field. Phosphorus ions extracted from discharged phosphine gas were implanted into single- and poly- crystalline silicon (c-Si and Poly-Si). We studied depth profiles of impurities and electrical properties of doped samples. Phosphorus ions were implanted into c-Si with <100> orientation to a depth of 100nm. Sheet resistances of c-Si and poly-Si decreased to 20ohm/_??_ and 100ohm/_??_, respectively. We believe that this doping technique should be useful for the fabrication of semiconductor devices. This doping technique is applicable to dope impurities uniformly over a large area.
The electrical properties of sputter deposited Ge polycrystalline films on fused quartz substrates at a deposition temperature of 475°C and film thickness of 400nm were investigated as a function of target voltage and Ar gas pressure. The Hall mobility of the films increased from 65 to 95 cm2/V•s as the target voltage and Ar gas pressure ratio decreased from 6 to l×102V/Pa. The carrier concentration decreased correspondingly. From these results, it is suspected that by decreasing the target voltage and Ar gas pressure ratio, i.e. the decrease of species energy in the sputtering process, the defects in the film due to the bombardment of arriving species emitted from the target reduced and the film properties had improved. In order to estimate the bombarding energy, Monte Carlo computer simulation of the energetic species behavior for various deposition conditions was carried out and incident energy at the substrate was calculated.
The dependence of refractive index on composition and its photo-induced variation have been calculated for the Ge-As-Se ternary system, using a random network model. It is found that a maximum increase in refractive index is obtained for As40Se60 and a maximum decrease is obtained for Ge33Se67. With this random network model, the compositions where the refractive index change has maximum values can also be simply obtained for other ternary systems.
Streamer electroluminescence (EL) is observed in anthracene single crystals. Impulse voltage is applied to anthracene crystals 1_??_4mm in thickness at the pressure range of 1.3_??_4.0×104Pa (100_??_300 Tort). When the applied voltage reaches a threshold voltage, normal EL suddenly changes to streamer EL. Next, when the applied voltage is lowered, the streamer EL returns to normal EL below the threshold voltage. Furthermore, the intensity of streamer EL is about ten times higher than that of normal EL. The peak wavelength of the streamer EL spectrum is the same as that of normal EL.