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Preparation of Tips for Tunneling Microscopes

IP.com Disclosure Number: IPCOM000101222D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Albrektsen, O: AUTHOR [+2]

Abstract

This procedure for preparing tips for use in an ultra-high vacuum tunneling microscopes involves alternate annealing and sputtering in accordance with the following sequence of steps: 1. Starting material is a tungsten (W) wire 1 (Fig. 1) of 0.1 mm thickness, either single-crystalline or polycrystalline. Wire 1 is etched using conventional chemical etching procedures. 2. Tip wire 1 is then mounted in a removable tip holder 2 comprising a hollow shaft 3 ending in a grip fixture 4 and adapted to receive miniature clamps 5 that can be arrested by means of a screw 6 to hold tip wire 1 in an axial position. Alternatively, tip wire 1 may be spotwelded to a 1 mm diameter stub (not shown). 3.

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Preparation of Tips for Tunneling Microscopes

       This procedure for preparing tips for use in an
ultra-high vacuum tunneling microscopes involves alternate annealing
and sputtering in accordance with the following sequence of steps:
1.   Starting material is a tungsten (W) wire 1 (Fig. 1) of 0.1 mm
thickness, either single-crystalline or polycrystalline.  Wire 1 is
etched using conventional chemical etching procedures.
2.   Tip wire 1 is then mounted in a removable tip holder 2
comprising a hollow shaft 3 ending in a grip fixture 4 and adapted to
receive miniature clamps 5 that can be arrested by means of a screw 6
to hold tip wire 1 in an axial position.  Alternatively, tip wire 1
may be spotwelded to a 1 mm diameter stub (not shown).
3.   For the insertion of tip holder 2 into the vacuum system and for
its transfer through various preparation stages, a transfer structure
7 may be used.
4.   After inserting transfer structure 7 (including tip 1) via an
airlock into a vacuum vessel, tip wire 1 may be heated by one of the
three methods listed below:
      a.   by electron bombardment of tip 1, using an electron
emitter, such as a barium oven, arranged preferably some 2-3 mm from
tip 1;
      b.   by electron emission from a tungsten wire which preferably
forms a loop around tip 1; and
      c.   by direct current heating.  In this case, tip 1 is spot-
welded to a small (1-1.5 mm) wire loop 9 threaded in two holes of an
insulating tube...