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
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ARSENIC IONS
BORON IONS
CHARGED PARTICLES
ELEMENTS
FLUIDS
ION IMPLANTATION
ION SOURCES
IONS
LIQUID METALS
LIQUIDS
METALS
PHOSPHORUS IONS
SEMIMETALS
SILICON
SURFACE PROPERTIES