A mass‐separating focused‐ion‐beam system for maskless ion implantation
| Autor: | R. L. Seliger, V. Wang, J. W. Ward |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Materials science
Ion beam business.industry General Engineering Analytical chemistry chemistry.chemical_element Focused ion beam Ion Condensed Matter::Materials Science Ion beam deposition Ion implantation chemistry Sputtering Physics::Atomic and Molecular Clusters Optoelectronics business Boron Microfabrication |
| Zdroj: | Journal of Vacuum Science and Technology. 19:1158-1163 |
| ISSN: | 0022-5355 |
| Popis: | The use of a focused ion beam for direct implantation of dopants into a semiconductor substrate results in appreciable simplification in the processing of semiconductor devices. We have demonstrated that liquid metal (LM) field‐ionization sources (based upon the electrostatic formation of an emitting cusp of liquid metal) offer the necessary high brightness to make focused ion beam microfabrication economically feasible. This paper reports upon two developments: (1) the development of eutectic‐alloy LM ion sources for the production of boron and arsenic for direct implantation of silicon devices, and (2) the development of a three‐lens variable‐energy focusing column that incorporates a mass‐separator of low aberration. Mass spectra of the ion emission of these sources show that the stoichiometric fraction of boron and arsenic is emitted. We have also demonstrated that the high vapor pressure of arsenic can be suppressed in the eutectic liquid metal, and that boron is predominantly emitted as a singly ionized species, while arsenic is emitted as both singly and doubly ionized species. A new focusing column has been developed that incorporates the new ion sources. It has the capability for focusing to sub‐micrometer dimensions with mass‐separation, a variable beam voltage of up to 150 kV, and a spot current of near 1 A/cm2. A high‐speed electrostatic‐deflection system with microprocessor control allows this machine to perform simple pattern exposures. Examples of the operation of this microfabrication system with eutectic alloy sources will be presented. |
| Databáze: | OpenAIRE |
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