Akira Hirakimoto

Measurement of hydrogen content in diamond like carbon thin films by ERDA

Abstract The hydrogen content in diamond like carbon (DLC) thin films has been determined by elastic recoil detection analysis (ERDA) using a 2.7 MeV He 2+ beam. The DLC films were prepared by an electron cyclotron resonance (ECR) microwave plasma chemical vapor deposition (CVD) system. Analysis of the spectra obtained reveals a uniform 29% concentration of hydrogen in the sub-surface region. Increasing the substrate temperature from room temperature to 250°C resulted in a decrease to 23% of the hydrogen concentration, accompanied by a 2.4 times increase of the films Knoop hardness. This clearly demonstrates the usefulness of the hydrogen concentration measurement in monitoring changes in the film properties. We also discuss other factors during deposition such as bias voltage, microwave power, etc., which influences the hydrogen contents in the DLC film.

The MeV ion implantation system “RFQ-1000” and its applications

Abstract Advanced VLSI devices are nowadays required to raise switching speed, to improve noise immunity and to minimize chip size. Presently, MeV ion implantation attracts much technological attention in the field of VLSI fabrication, because it is expected to be one of the most feasible solutions to those demanding requirements. In order to realize such prospective expectations, an RFQ (radio-frequency quadrupole) accelerator was applied for the first time to the field of ion implantation and a MeV ion implantation system “RFQ-1000” has been developed. First, we briefly refer to the background of the system development, putting emphasis on the RFQ. Next an outline is given of the system configuration and features. Following, detailed performances of the system are described, i.e., beam current capability, energy variability, dose uniformity, particle performance and so on. Then we move onto the viewpoint of applications. The current status of device applications by the MeV ion implantation are briefly reviewed. Finally future applications of the system to the field of compound semiconductors and to the surface modification of materials are presented.

An RFQ accelerator system for MeV ion implantation

Abstract A 4-vane-type Radio-Frequency Quadrupole (RFQ) accelerator system for MeV ion implantation has been constructed and ion beams of boron and nitrogen have been accelerated successfully up to an energy of 1.01 and 1.22 MeV, respectively. The acceleration of phosphorus is now ongoing. The design was performed with two computer codes called SUPERFISH and PARMTEQ. The energy of the accelerated ions was measured by Rutherford backscattering spectroscopy. The obtained values agreed well with the designed ones. Thus we have confirmed the validity of our design and have found the possibility that the present RFQ will break through the production-use difficulty of MeV ion implantation.