Qingchuan Chen

VACUUM ARC PLASMA TRANSPORT THROUGH A MAGNETIC DUCT WITH A BIASED ELECTRODE AT THE OUTER WALL

Metal plasma formed by a vacuum arc plasma source can be passed through a toroidal-section magnetic duct for the filtering of macroparticles from the plasma stream. In order to maximize the plasma transport efficiency of the filter the duct wall should be biased, typically to a positive voltage of about 10–20 V. In some cases it is not convenient to bias the duct, for example if the duct wall is part of the grounded vacuum system. However, a positively biased electrode inserted into the duct along its outer major circumference can serve a similar purpose. In this article, we describe our results confirming and quantifying this effect. We also show the parametric dependence of the duct transport on the experimental variables.

Low pressure plasma immersion ion implantation of silicon

Mono-energetic plasma immersion ion implantation (PIII) into silicon can be attained only under collisionless plasma conditions. In order to reduce the current load on the high voltage power supply and modulator and sample heating caused by implanted ions, the plasma pressure must be kept low (<1 mtorr). Low pressure PIII is therefore the preferred technique for silicon PIII processing such as the formation of silicon on insulator. Using our model, we simulate the characteristics of low pressure PIII and identify the proper process windows of hydrogen PIII for the ion-cut process. Experiments are conducted to investigate details in three of the most important parameters in low pressure PIII: pulse width, voltage, and gas pressure. We also study the case of an infinitely long pulse, that is, dc PIII.

Steady-state direct-current plasma immersion ion implantation using an electron cyclotron resonance plasma source

We have developed a new direct-current (DC) plasma immersion ion implantation (PIII) technique by using a conducting grid positioned between the plasma source and sample chuck. In order to decrease the working gas pressure and increase the plasma density, an electron cyclotron resonance (ECR) plasma source was used in our experiments. In this paper, the experimental parameters and results pertaining to DC-PIII using an ECR plasma source are described. The uniformity of the ion dose and the energy monotonicity are discussed. Our experimental results indicate that DC-PIII is a novel and potentially useful technique for planar sample processing, particularly in microelectronics applications.

Macro-particle free metal plasma immersion ion implantation and/or deposition in a multifunctional configuration

For high-dose metal ion implantation, the use of plasma immersion offers the high-rate advantage, but the simultaneous formation of a surface film along with the sub-surface implanted layer is sometimes a detriment. In this work, we describe a metal . plasma immersion approach in which pure and macro-particle free implantation metal andror gas ions , pure deposition without ion implantation, or dynamic metal ion beam assisted deposition and gaseous plasma immersion ion implantation DIBAD metal . and gas plasma immersion can be obtained. We have demonstrated the technique by carrying out Ti and Ta implantation at .

Inner surface ion implantation using deflecting electric field

Abstract Because of its non line-of-sight nature, researchers have recently focused on plasma immersion ion implantation (PIII) to enhance the properties of inner surfaces of industrial components to combat wear and corrosion. However, theoretical simulation has shown a relatively dim prospect because of the limitation on impact energy and retained dose. In this paper, we describe a procedure to improve the efficiency of inner surface implantation by using a symmetrical experimental setup and deflecting electric field. Improvements of 43% and 71% are observed for the implantation depth and retained dose, respectively. Since a large portion of the ions implanted into the interior surface originate from outside of the bore, a longer pulse-width will be more beneficial.

Enhancement and stabilization of cathodic arc using mesh anode

The performance and characteristics of a cathodic arc deposition apparatus consisting of a titanium cathode, an anode with and without a tungsten mesh, and a coil producing a focusing magnetic field between the anode and cathode arc investigated. The arc voltage V/sub a/ is measured with a fixed arc current for an anode diameter of 40 mm. The relationship between V/sub a/ and the magnetic field B with and without a mesh is obtained. In addition, the relationship between the arc current I/sub a/ and V/sub c/, the voltage to which the artificial transmission line was charged, is measured with and without the mesh to determine the minimum ignition voltage for the arc when the anode hole diameter is 40 mm. The arc resistance increases with the focusing magnetic strength B and decreases when using the mesh. Our results indicate that the high transparency and large area of the mesh allows a high plasma flux to penetrate the anode from the cathodic arc. The mesh also stabilizes the cathodic arc and gives better performance when used in concert with a focusing magnetic field.

Steady-state direct-current plasma immersion ion implantation using a multipolar magnetic field electron cyclotron resonance plasma source

In semiconductor plasma immersion ion implantation (PIII) applications such as the synthesis of silicon-on-insulator by hydrogen PIII and ion cut, only ions arriving at the top surface of the sample stage are important. The ions implanted into the other surfaces of the sample chuck actually not only decrease the efficiency of the power supply and plasma source but also give rise to metallic contamination. In addition, low energy ions introduced by the initial plasma sheath propagation, pulse rise time, and pulse fall time introduce a large surface hydrogen concentration that creates surface damage and affects the wafer bonding efficacy. We have theoretically demonstrated direct-current PIII (DC-PIII) which retains the x–y immersion characteristic while simultaneously reducing this low energy ion component, obviating the need for the expensive power modulator, and extending the voltage ceiling that is no longer limited by the vacuum chamber and power modulator. In this article, we describe our hydrogen DC-...

Effects of high temperature ion implantation on titanium nitride coated carbide cutting tools

Summary form only given. The effects of high temperature nitrogen and aluminum ion implantation and plasma implantation on titanium nitride coated carbide cutting tools are investigated. Aluminum implantation is used to enhance the high temperature oxidation wear resistance, and plasma nitriding and high-temperature ion implantation are used to further improve the surface microhardness and corrosion resistance. TiN films are deposited on carbide cutting tools by vacuum arc ion plating, in which a shutter plate is used to avoid line of sight transit of macro-particles from the cathode to the substrate. Nitrogen and aluminum ion implantation at elevated temperature (300-600/spl deg/C) is then achieved in a multi-function ion implantation system. The effects of different substrate temperature, implantation dose and implantation energy on the surface properties are assessed. The corrosion measurements are carried out in a NaCl solution using electrochemical impedance spectroscopy. The oxidation resistance studies are carried out in air at 800/spl deg/C using continues and discontinuous method. The surface microhardness, crystal structure and microstructure are measured by microhardness measurement, XRD, SEM and AES. The process is applied to industrial cutting tools in the production line, and the results are reported in this paper.