Ablation plasma ion implantation.
Qi, Bo
2002
Abstract
The novel hybrid technique, Ablation Plasma Ion Implantation (APII), has been characterized and optimized for ion implantation and/or thin film deposition. In APII, a solid target is ablated by a laser; the resulting plasma plume is the source of ions, which are accelerated to high energy by a negative bias voltage imposed on the substrate. The ions are implanted into the substrate, and the neutral atoms in the ablation plume deposit on the substrate in the form of a thin film. Two configurations of APII are characterized and compared. The parallel target-substrate configuration yields ion-beam-assisted deposition and/or ion implantation, and the perpendicular target-substrate configuration yields pure ion implantation mode. A novel theory of the ion matrix sheath has been developed for APII. The ion current predicted by the Child-Langmuir sheath theory matches well with the experimental ion current. Two different target-substrate orientations have been compared for APII. Parallel target-substrate orientation yields ion-beam-assisted-deposition and ion implantation; to prevent arcing, a laser-voltage delay of several microseconds is required for this mode. For the optimized perpendicular target-substrate orientation, the laser can be fired during the voltage pulse, thereby accelerating ions to full energy. Furthermore, the ion dose is higher than that of the parallel target-substrate orientation by a factor of two. The parameters of plasma plumes have been thoroughly characterized by numerous diagnostics, which include electrical characteristics, optical emission spectroscopy, dye laser resonance absorption photography, resonant/non-resonant interferometry, and Langmuir probe. The total number of ions measured by Langmuir probe, and resonant interferometry, is in the range of 10<super>14</super> ions per laser pulse. Ion dose measured by plasma diagnostics, has been correlated to the ion dose obtained from material analysis, including sputtering yield calculation, X-ray Energy Dispersive Spectroscopy and X-ray Photoelectron Spectroscopy. The retained and delivered ion doses are in the range of 10<super> 12</super>/cm<super>2</super> per pulse, which is favorable compared to the ion dose obtained from conventional Plasma Immersion Ion Implantation (PHI). The APII ion implantation efficiency is estimated to be about 2%. Ion acceleration and implantation was demonstrated for both of the APB configurations. The feasibility of APII was verified by Cross-Sectional Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. For parallel target-substrate configuration, the average deposition rate is 0.0075 nm/shot for the Ti -10 kV APII film. Atomic Force Microscopy implemented at Timken Research Lab indicates that the -4 kV APII film has the smoothest surface. Scratch tests performed at Timken Research lab also prove that APR produces excellent film adhesion.Subjects
Ablation Plasma Ion Implantation Laser Ablation
Types
Thesis
Metadata
Show full item recordCollections
Remediation of Harmful Language
The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.
Accessibility
If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.