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Ion Beam Machining of Very Sharp Points

IP.com Disclosure Number: IPCOM000044002D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Dietrich, HP: AUTHOR [+3]

Abstract

Directed ions are used to sputter off material from rotated rods or pins to obtain extremely sharp points, the starting material being a chemically or mechanically pre-prepared point. The proposed technique is reproducible and applicable to a wide variety of materials, such as silicon oxide or tungsten. The resulting tips may be employed in very high resolution microscopes, e.g., in scanning tunneling microscopes that typically use tungsten tips or in near-field optical microscopes that use sharp tips made of rods of transparent material. Further applications may be in other scientific instruments or mass storage devices. The figure schematically illustrates the ion beam system used and the arrangement of the pointed rod that is to be machined.

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Ion Beam Machining of Very Sharp Points

Directed ions are used to sputter off material from rotated rods or pins to obtain extremely sharp points, the starting material being a chemically or mechanically pre-prepared point. The proposed technique is reproducible and applicable to a wide variety of materials, such as silicon oxide or tungsten. The resulting tips may be employed in very high resolution microscopes, e.g., in scanning tunneling microscopes that typically use tungsten tips or in near-field optical microscopes that use sharp tips made of rods of transparent material. Further applications may be in other scientific instruments or mass storage devices. The figure schematically illustrates the ion beam system used and the arrangement of the pointed rod that is to be machined. In a chamber (not shown) an ion source directs an ion beam at the rod which is rotated about its longitudinal axis, as indicated. Process parameters for machining, e.g., a tungsten tip can be chosen as follows: - Ion beam: Argon, with ion density of 0.3 mA/cm2 at 500 eV and a system pressure of 2 x 104 Torr. The beam is directed at the tip, as illustrated, at an angle of incidence of 45 which is near the maximum sputter yield. - The rod is rotated at one resolution per second. - Duration: After about 5 hours the tip is sharpened and any secondary tips (from preceding processes) removed. The time required depends, however, on the initial sharpness and shape of the rod, on the etch rat...