The effects of metalloid elements (B and Si) on the crystallization in amorphous Ni77B23-xSix (x=3, 5, 6.5) and Ni77.5B14.6Si7.9 alloys were investigated by means of electrical resistance measurement, thermal analysis (DSC) and X-ray diffractometry. The crystallization always started with the formation of fcc-Ni (containing metalloid elements), which was followed by the precipitation of Ni3B. The crystallization temperature and the activation energy for the crystallization of Ni both increased with increasing Si content in alloys. The Avrami exponent found for the crystallization of Ni was 1.5 showing no compositional dependence. The increase in thermal stability by Si addition is discussed from the difference of bonding strength between Ni-B and Ni-Si atom pairs.
An active-matrix addressed vacuum fluorescent display (VFD) has been investigated to develop an on-chip image display and a multichip character display. It consists of low energy cathodoluminescent phosphor elements deposited on the respective MOS transistors and an area cathode. In the case of conventional VFD, the phosphor lighting is turned off by cutting-off the elect ron irradiation to the phosphor. But, for the active-matrix addressed VFD, the electron flow is controlled continuously by a transistor to produce a gray shade. Therefore, there are certain physical restrictions to be satisfied by the components for the device to perform. This paper considers the physical mechanism of operation and it clarifies the relations among the physical parameters of materials composing the device. Based on these relations, examples applied to the actual devices are presented.
Photo ashing process as a resist stripping method in microlithography cause less damage to devices than the conventional Oz plasma ashing. Resist stripping charactaristics and its mechanisms in the photo ashing were investigated with novolak base photoresist and some other resists. There are two types in photo ashing mechanism of polymer resist. The photo ashing of PMMA is the photomechanical stripping by deep ultraviolet radiation (direct photo ashing). The photo ashing of cyclised rubber base and novolak base photoresists are the reactive stripping by active oxygen produced by deep ultraviolet radiation (photo assisted ashing). In the case of the reactive stripping of the resists, it is required that the active oxygen effectively attack the resist surface, since the reaction of resist removing is limitted to the surface of the resist.