The Development and Evolution of Ion Implanters in the Semiconductor Industry
- Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M5 4 WT (United Kingdom)
By the end of the 1960's, the development of ion beam systems for isotope separation and materials research had reached the stage at which knowledge bases in the areas of ion beam formation and transport and the physics of atomic collisions in solids made it practical to consider the use of ion implantation as a means of modifying the near surface properties of solid materials. The beam currents and energies available made the technique particularly compatible with the doping requirements of the silicon devices being produced at that time. However, incorporation of the technique into a high volume manufacturing environment required the immediate development of new target handling facilities and improvements in machine reliability. While the manner in which ion implanters have evolved over the past forty years has continued to be dictated by the changing demands of the silicon processing industry, the dramatic reduction in transistor size and the increase in integrated circuit complexity have had significant implications for the qualities of the ion beams themselves, particularly in high current, ultra-low energy applications. Since the first commercial implanters were introduced, highly developed medium current, high current and high energy machines have evolved. In the medium current and high energy sectors, well understood ion optical principles have enabled ingenious and highly effective beam formation and transport systems to be designed. As these machines evolved, extensive studies of the implanted material using ion beam based techniques such as Rutherford backscattering and channelling provided a growing understanding of the fundamental radiation damage and annealing processes that are inevitably associated with the implantation process. For high current machines, particularly those operating in the so-called eV implantation range, beam formation and transport processes become considerably more complex and established ion optical design principles must be combined with detailed considerations of the roles of emittance, space charge and beam plasma characteristics if beams compatible with production worthy ultra-shallow junction formation are to be obtained. For these shallow, high dose implants, the proximity of the surface has a significant effect on the radiation damage build-up and annealing processes. To develop an understanding of the physics of some aspects of these processes, high depth resolution analytical techniques such as medium energy ion scattering have been applied. In the present review, the process based evolution of ion implantation equipment is discussed alongside a consideration of the contribution made by the growth in understanding of the physics of both the beams themselves and the ion collection and radiation damage processes occurring in the implanted silicon.
- OSTI ID:
- 21251693
- Journal Information:
- AIP Conference Proceedings, Vol. 1066, Issue 1; Conference: 17. international conference on ion implantation technology, Monterey, CA (United States), 8-13 Jun 2008; Other Information: DOI: 10.1063/1.3033647; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANNEALING
ATOM COLLISIONS
BEAM CURRENTS
INTEGRATED CIRCUITS
ION BEAMS
ION IMPLANTATION
ISOTOPE SEPARATION
KNOWLEDGE BASE
MANUFACTURING
PHYSICAL RADIATION EFFECTS
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SEMICONDUCTOR MATERIALS
SILICON
SILICON IONS
SPACE CHARGE
SURFACE PROPERTIES
TRANSISTORS