Surface phenomena in liquid metal alloys with application to development of a liquid metal ion source of B and As
A liquid metal ion (LMI) source is a low volatility liquid metal film which flows to the apex of a solid needle support structure. Subsequent application of a high electric field deforms the liquid and results in ion emission. Considerable interest has been shown in development of LMI sources capable of producing a variety of technologically important ions. For implantation of silicon, for example, B is the preferred p-type dopant, while As and P are the preferred n-type dopants. It has been difficult to construct long-lived ion sources based upon these species because B possesses a high melting point and reacts strongly with most refractory metal supports, while As and P have high vapor pressures. To overcome these difficulties, the material and thermochemical properties of liquid metal alloy surfaces were studied. A number of successful contact systems were identified for B, while the development of a LMI source of As was completely solved. To lower the chemical reactivity of B alloys, it was necessary to utilize nonmetallic support structures. In these cases wettability of B based alloys is governed by surface segregation of low-level, low-surface tension impurities within the alloys that inhibit reaction between the alloy and substrate. Coating the substrate with a material having a high affinity to carbon (e.g., B, or Si) acts to tie up the segregated material and promote wetting.
- Research Organization:
- Oregon Graduate Center, Portland (USA)
- OSTI ID:
- 5214530
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
ION IMPLANTATION
ARSENIC IONS
BORON IONS
LIQUID METALS
ION SOURCES
SILICON
PHOSPHORUS IONS
SURFACE PROPERTIES
CHARGED PARTICLES
ELEMENTS
FLUIDS
IONS
LIQUIDS
METALS
SEMIMETALS
640301* - Atomic
Molecular & Chemical Physics- Beams & their Reactions