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As a crystallization process, the field-aided lateral crystallization (FALC) technique has some outstanding advantages, such as high crystallization rate and low temperature. In this study, an electric field was directly applied between source and drain areas of H shape patterns using the Mo-W interconnecting layer. The effects of the current density and the electrical field strength on the crystallization behavior were investigated. Such crystallization behaviors are attributed to the coexisting effects of electromigration and potential gradient. In addition, the dependence of the degree of crystallization on the current density was studied and the microstructure crystallized by FALC was compared with the microstructure crystallized by metal induced lateral crystallization (MILC) process.

Summary form only given. During the plasma immersion ion implantation (PIII) process, ions are typically created by an external plasma source, such as electron impact glow discharge using hot filaments, radio frequency, electron cyclotron resonance, metal arc, and so on, There is, however, a less obvious ion formation mechanism by the high voltage itself, especially for a long pulse duration or at high working pressure, as shown by the implantation current not decreasing monotonically as predicted by the Child-Langmuir law. A proof of this secondary phenomenon is that the measured total current sometimes increases dramatically in a low vacuum sustained by RF glow discharge. Another example is that the current can gradually rise after a short delay during long pulse, hot filament glow discharge PIII. These phenomena can be attributed to high voltage ionization during the PIII process and are related to the gas pressure, high voltage pulse duration, target size, target materials, and so on. In this paper, we will present supporting experimental data in addition to a theoretical analysis.

Summary form only given. Plasma immersion ion implantation (PIII) is a promising technique for surface modification of materials. Because of its non line-of-sight process, there is the intriguing possibility of implanting "interior" surfaces. If the radius R of a bore is many Debye lengths, the bore will be plasma-filled and it is possible to implant into the sidewalls of the bore. Sheridan (1993) has found that the important length scale is the ion-matrix overlap, D=(/spl epsiv//sub 0//spl phi//en/sub 0/)/sup 1/2/ where /spl phi/ is the (negative) target potential and n/sub 0/ is the (uniform) plasma density. His recent research results indicate that ion implantation in small bores (R/spl les/D) is not very hopeful because the ion-matrix sheath overlap reduces the impact energy of the ions. We are proposing to use an auxiliary electrode, a conductive cylindrical bore which potential is always zero at the axis of the cylindrical bore, to improve the impact energy. We have calculated the structure of the ion-matrix sheath in an infinitely long cylindrical bore (R/spl les/D) with the auxiliary electrode and analyzed the dependence of its radius on the electric field in the bore. Our results show that the auxiliary electrode improves the distribution of the potential and electric field in the cylindrical bore.

Summary form only given. The high voltage and electromagnetic field environment poses a big challenge to a control system for plasma immersion ion implantation (PIII). The automation process must be immune to electric field interference produced by the high voltage pulse power supply, radio frequency plasma generator, MEVVA plasma sources, and so on. We have recently designed and installed a distributed control system, PIIIDCS, for Pill facility. Programmable logic controllers (PLC) are used as the field control stations because of their good anti-interference ability and good real time response. A DH-485 network is used as the communication link between the field controllers and the management station in order to improve the robustness and reliability of the system. The newly developed interface is designed to work in a graphic mode in Microsoft Windows 95. Test runs have shown that the system is reliable, flexible, and easy to operate. The development of this novel control system will expedite the development of commercial PIII instrumentation.

Summary form only given. Previous work concentrated on the determination of the ion-matrix sheath and the temporal evolution of the plasma sheath in a small cylindrical bore for zero-rise-time voltage pulses during plasma immersion ion implantation (PIII). Because realistic voltage pulses have a finite rise time, this paper addresses the temporal evolution of the plasma sheath in a small cylindrical bore with an auxiliary electrode for different rise times by solving Poisson's equation and the equations of ion continuity and motion numerically using the appropriate boundary conditions. The ion density, flux, dose, energy, energy distribution, and average impact energy on the surface of the target for different rise times are determined and compared to the case when the auxiliary electrode is absent. Our results predict a substantial improvement of the impact energy during PIII of a cylindrical bore when an auxiliary electrode is employed even for finite-rise-time voltage pulses.

Summary form only given, as follows. Plasma immersion ion implantation (PIII) has a number of advantages over conventional beam-line ion implantation techniques. One of them is the ability to implant "interior" surfaces that are not line-of-sight accessible. The inner surfaces of many industrial components, such as dies, bushings, pipes, and so on are difficult to process and inner surface modification using PIII is both interesting scientifically and commercially. We have proposed a method to improve the impact energy of ions implanted into the interior sidewalls of cylindrical specimens by using an auxiliary electrode having a zero potential. The ion-matrix sheath and the temporal evolution of the plasma sheath in a small cylindrical bore with an auxiliary electrode have been calculated for an auxiliary electrode of a regular radius. In this paper, the effects of the auxiliary electrode radius are discussed. We compute the critical radius of the cylindrical bore when the ion-matrix sheath just overlaps as well as the number of implanted ions. The ion density, flux, dose, energy, energy distribution, and average impact energy are also determined for different radii of the auxiliary electrode by solving Poisson's equation and the equations of ion continuity and motion numerically. Our results provide the theoretical background for the implementation of an auxiliary electrode in a PIII instrument.

Summary form only given. We have devised a variety of treatment processes using PIII, including radio-frequency (RF) plasma nitriding, RF plasma nitriding and nitrogen PIII, Ti deposition in conjunction with nitrogen PIII (IBED), as well as Cr deposition followed by nitrogen PIII (IBED). To assess the efficacy of the processes, the microhardness and mass loss due to wear were measured for both the untreated and treated 45 samples. A salt fog test was also conducted to evaluate the resistance against rusting. Our experimental results show that the microhardness and resistance against rusting of the treated 45 steel samples are much improved, and the mass loss due to wear is reduced substantially. In this paper, we compare the effectiveness of each treatment technique in addition to showing supporting data.

Summary form only given. We have recently developed a 10kV solid state power modulator for the processing of industrial bearings by plasma immersion ion implantation. According to our research results, high energy implantation is not preferred in the treatment of industrial bearings because of the geometry of the races, and a dedicated and less expensive power supply will suffice. In our new design, optical communication modules are used to synchronize the control pulse of each IGBT and a new method is used to generate power for the IGBT gate drive in the solid state modulator In addition to a maximum voltage of 10kV, our inexpensive power modulator can output pulses 2 to 100 microseconds in duration with a rise time of 2 microseconds. The maximum pulsing frequency is 2kHz. We will present the details of the design and the experimental results in this paper.

Summary form only given, as follows. Dual plasma deposition incorporating gaseous plasma and vacuum arc plasma is a useful method to synthesize thin films. Although the gaseous plasma density is quite uniform in the vacuum chamber, the density of the output of a vacuum arc plasma source is much less uniform in both the radial and axial directions. At the same time, since ions emitted from a vacuum arc plasma source have high axial velocity, the radial plasma density cannot be easily changed. As a result, it is difficult to perform large area deposition / implantation uniformly. In order to improve the uniformity of the plasma density, we apply an AC voltage onto the substrate. When the applied voltage is positive, the ion velocity is reduced and the plasma becomes more uniform due to diffusion and the radial velocity of the incoming ions. In our particle-in-cell (PIC) simulation, we set the negative voltage and pulse width to predefined values according to the radial ion velocity to investigate the effects of the positive applied voltage, positive voltage pulse width, and the distance of the substrate on the uniformity of the deposited film. Our simulation results clearly demonstrate that a proper AC voltage can improve the uniformity of the thin film.

Summary form only given. In order to make titanium oxide films that possess good blood compatibility and can withstand a high contact stress, we are using a novel hybrid plasma fabrication technique combining plasma nitriding and plasma immersion ion implantation (PIII). The titanium alloys are first nitrided in a nitrogen plasma and then the TiO/sub x/ coating is produced by plasma immersion ion implantation utilizing titanium metal plasma and reactive plasma oxidation. The Ti-N layer produced by plasma nitriding can withstand a high contact stress and the titanium oxide coating generated by PIII yields improved biocompatibility and tribological properties. In this paper, the plasma fabrication processes are described. In addition, the tribological properties are assessed by measuring the microhardness and wear resistance, whereas the microstructures and surface characteristics are evaluated by using glancing X-ray diffraction, atomic force microscopy, and transmission electron microscopy. Our results show that titanium alloys with surface duplex PIII-TiO/sub x//Ti-N films have better load bearing capacity than that of PIII-TiO/sub x/ films.

Summary form only given. Low voltage plasma immersion ion implantation (pill) has been demonstrated to have great potentials in industrial applications. The process is characterized by a thin plasma sheath and high ion flux compared to conventional high-voltage elevated-temperature plasma immersion ion implantation. Hence, it is more suitable for samples with an irregular shape. Our work on AISI304 stainless steel materials shows that both the tribological properties and corrosion resistance of the treated samples can be enhanced by this method. In this paper, we focus on the effects of the treatment temperature on the structure and corrosion resistance of the samples at a sample bias of 2 kV. After treatment, expanded austenites (/spl gamma//sub N/) is formed in the top surface layer as revealed by glancing-angle X-ray diffraction (XRD), and the amount of the /spl gamma//sub N/ phase increases with the treatment temperature up to 450/spl deg/C. Meanwhile, the thickness of the modified layers varies exponentially with the sample temperature. The corrosion resistance is also substantially enhanced as shown by polarization test and SEM. The polarization curves demonstrate that the electrochemical properties also depend on the treatment temperature. In fact, the synergetic effect of the sample temperature and high ion flux (dose rate) determines the final surface properties of the treated samples.