|
|
|
|
|
|
|
Semiconductor Trace Metals The detection and quantification of trace metals is an important analytical task in the semiconductor industry. Due to the high mass resolution and the very low noise level, excellent detection limits down to 107 atoms/cm2 can be obtained. These limits are achieved even from small areas.  Ultra-Shallow Depth Profiling Increasingly, the semiconductor industry is making use of low energy ion implants for shallow junction formation. These implants, which are often made at between a few hundred to a few thousand electron volts, require an analysis capability that will allow depth resolution < 1 nm to be obtained. A significant fraction of the implanted dose is located within the top few nm. In order to ensure an accurate dose measurement, sputtering conditions must be chosen such that the transient width is well below 1 nm and that sample roughening is minimized.   
Handling Tool Contamination Large area analysis was used to map silicon wafers picked up from storage boxes by standard vacuum suction tweezers. Ion mapping revealed an imprint of the tweezers' jaws on the surface visible in e.g. the sodium ion image. In this case the corresponding contamination originates from isopropanol with which the tweezers were routinely pre-cleaned. |
|
|
|
Details of a spectrum from a Silicon wafer surface. High mass resolution and accuracy allow the unambiguous identification of trace metals. Depth Profile of a 3keV BF2 implant in Silicon 500 eV O2 sputtering Depth Profile of a 3keV As implant in Silicon 500 eV O2 sputtering 10 Depth Profiles of a 700 eV B implant in Silicon 500 eV O2 sputtering average dose: 2.997614 cm2 RSD: 0.49 %  An ion distribution map of 23Na+ with a field of view of 5 x 5 cm2 taken from a silicon wafer. (Reference: R. Treichler, Siemens AG, München) |