Change in film properties, especially resistivity and the thermal dependence of resistance, that are due to differences in the thickness and the temperature of heat treatment of Ta-Si-C films developed as high resistivity materials were investigated. From these results, the mechanism of film thermal changes was discussed. Further, the effect of film thickness on the performance of Ta-Si-C thin film thermal printing heads was also investigated. The results show that; (1) a ln ρT-1/2 relationship between resistivity and temperature in Ta-Si-C thin films holds good over a wide temperature range from 293 to 873 K, (2) resistivity is dependent of film thickness when film thickness is less than 2000 (greater resistivity in thinner films), (3) the thermal dependence of resistance is dependent on film thickness when film thickness is less than 3000 (greater thermal dependence in thinner films), (4) resistivity is increased and thermal dependence of resistance is decreased by heat treatment below 400 , and that (5) excellent performance is achieved when Ta-Si-C thin films greater than 3000 in thickness are used as the thermal printing head resistor film.

We have studied in detail the effect of gas flow rates on the film properties of low-temperature (300) polycrystalline silicon (poly-Si) films prepared by conventional plasma enhanced chemical vapor deposition (13.56 MHz) with SiF4/SiH4/H2 gases. The effect of SiH4 flow rate on crystallization is shown to be large. A small amount of SiH4 with high SiF4 and H2 flow rates (50[H2]/[SiH4]1200, 20[SiF4]/[SiH4]150, 1[H2]/[SiF4]16) is important to form poly-Si films. The poly-Si films deposited under such optimized conditions had shown preferential 〈110〉-orientation and the crystalline fraction is estimated to be more than 80%. The deposition rates are in the range of 5-30 nm/min. The conductivity is in the range of 10-8-10-6 S/cm. Further, the electrical conduction indicates an activation type, and the activation energy is in the range of 0.5-0.6 eV.

The 1 4 optical switch array for wavelength division multiplexing system has been demonstrated where four 14 waveguide digital optical switches have been integrated into one chip. Tape fiber is used as the connection between switch modules to avoid an interconnection fiber jungle. The architecture can be adapted to any number of wavelength channels. Redundant optical switch stage for crosstalk rejection has been used to attain a low crosstalk level. Electro-optic switching is used to attain low power consumption indispensable for routing large wavelength channels.

In this paper, it is presented that the experimental results of the magnetic bubble propagation in dual conductor current access test circuits, where the bubble-driving fields can be generated by applying the bipolar pulse currents to the apertured conducting sheets. Under the driving conditions that the current density for the first conducting sheet (I1) was at 0.5 mA/µm, for the second conducting sheet (I2) was at 1 mA/µm, and the frequency of these currents was at 200 kHz, the bias margin for the propagation normal to the currents flow was obtained as much as 5 Oe.