ISSN:
0741-0581
Keywords:
Metal evaporation
;
Shadowing
;
Computer simulation
;
Resolution
;
Grain
;
Void space
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Natural Sciences in General
Notes:
This paper addresses the question of what is the very best deposition that can be achieved by metal evaporation shadowing. It deals, therefore, with the resolution attainable in metal shadowed specimens. The analysis disregards interatomic attractions (nucleation, crystallite formation, decoration) and generates depositions solely on the basis of probabilities of vacant, single, and multiple atom landings at different points on a substrate.The treatment starts by showing that random number generation can be used to simulate reasonably the evaporation of metal atoms from a shadowing source and their deposit on a substrate. A Fortran program tabulates and displays these simulated atom landings. The analysis shows that one can never expect to obtain a perfectly uniform deposit; some areas will always be heavily filled while others will be lightly filled or vacant. Resolution is thereby limited. The analysis shows how a deposit becomes more uniform as the number of atoms deposited increases. It predicts optimal amounts of deposition for various shadowing angles. The analysis also provides a rationale for the way in which deposition grain coarsens and resolution worsens as the angle of shadow is made more steep.Computer-generated “ideal” depositions are compared with real shadow grains achieved under equivalent experimental conditions. The simulations are also compared with deposits achieved by novel shadowing methods. Ways to improved metal evaporation technique are suggested by the analysis and these are discussed.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jemt.1060020405
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