Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400772
Title: High quality high current ion beam generation and transport systems including plasma-based space charge neutraliser
Author: Ito, Hiroyuki
Awarding Body: University of Salford
Current Institution: University of Salford
Date of Award: 2003
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Abstract:
This thesis discusses the development of an ion beam generation and transport system for the purpose of high current ion implantation and presents a method to achieve high quality beam generation and high transport efficiency. An advanced method of achieving ideal space charge neutralization of an ion beam as well as charge neutralization of implanted targets has also been developed and presented. This study was carried out in five main categories as described below. 1. Beam optics: The optical properties of the ion beam have to be well controlled through various beam transport devices. Beam transfer matrix calculation and Poisson's equation solver were used to determine beam optics. 2. Plasma generation: The ion beam is extracted from a plasma generated in the ion source. Therefore, the quality of ion beams depends largely on the characteristics of the source plasma. Plasma diagnostic tools were used to understand the desired plasma conditions. 3. Space charge neutralisation: Space charge neutralisation is essential to transport high perveance beams because a beam without neutralisation develops a high electric potential in itself that would scatter beam ions away. A plasma based charge neutraliser "Plasma Flood System" was developed to maintain space charge neutrality during implantation. 4. Low energy beam extraction and transport: Beam extraction and transport become difficult at lower energy due to growth of emittance and space charge. Beam divergence had to be minimized by tight optical control. 5. Microwave plasma sources as ultimate ion source: A microwave source was developed to obtain high current, ultra clean ion beams and long source life. The characteristics of microwave plasmas differ significantly from whose generated by other methods such as DC excitation. The source achieved the highest recorded beam currents for various species. All the technology and the methods described above were combined to develop a state-of-the-art high current ion implanter that has achieved world leading beam performance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.400772  DOI: Not available
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