Abstract
An instrument is described which combines the high resolution imaging capability of an STM with chemical analysis and mapping with similar resolution. By varying the STM tip voltage either a tunnelling current is measured for imaging or the tip acts in field emission mode, ejecting electrons which are focussed onto a sample surface. Secondary electrons are then detected at grazing angles to the sample surface to identify chemical species on the surface. Examples are given of elastic, surface and bulk plasmon peaks from Si, graphite and gold surfaces. The patent also covers innovative electron ion optical assemblies fabricated on the micron scale to monochromate and focus the primary beam to nanometre dimensions. Tip and sample transfer systems allow for changing these under UHV for rapid analysis. By using low energy electrons samples remain undamaged after analysis, making the technique ideal for biological and semiconductor surfaces.
| Original language | English |
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| Patent number | 0002367.1 |
| Publication status | Published - 2000 |