Probe technology aids semiconductor analysis

Advanced laser 3D atom probe technology can be used on silicon devices.

Atom by atom analysis of semiconductor materials has just become a reality with the announcement from Oxford Nanoscience that its 3DAP advanced laser 3D atom probe technology can be used on silicon devices.

For the first time semiconductor device manufacturers will be able to determine both the elemental identity and position of individual atoms in their products.

With decreasing device dimensions, the unique capabilities of this technique will be critical for the design,engineering and manufacturing of next generation devices.

Manufacturers will also be able to improve their understanding of how manufacturing processes affect device structure on the atomic scale and how these changes influence device yields, performance and reliability.

The 3DAP works by evaporating individual atoms from a semiconductor sample, measuring their atomic mass and then calculating their position in the sample's three-dimensional structure.

A detailed three dimensional atomic model of the sample can then be visualised using software reconstruction.

Oxford Nanoscience, which has the world's largest installed base of conventional 3DAP machines that use high voltage pulses to evaporate atoms from conductive samples, is now using a laser excitation mechanism to open up the technique to semiconductor samples.

Impressive results have been produced on silicon samples of different conductivities and a variety metal multilayer structures, including metal oxide layers, grown on a silicon substrate.

The new instrument uses the company's well established 3DAP analysis system (originally developed at the University of Oxford, UK) combined with femtosecond laser excitation.

The three-dimensional atom maps produced by the system make it possible to actually view the structure at the atomic scale and the proprietary analysis package (also developed by Oxford Nanoscience) includes a comprehensive suite of data analysis tools that allow complete extraction of quantitative information.

Accurate chemical compositions can be obtained for all or selected regions of the data with element detections limits in the range of 1-100ppm.

Not only can the instrument provide visualisation of atomic structure in a way not previously attainable, but results are obtained fast and with outstanding mass resolution.

Sample analyses of millions of atoms can be run in just 10 minutes and the industry leading mass resolution means that very small quantities of atoms with similar atomic mass can be separated out by the instrument, which could be crucial when looking at small dopant concentrations.

Mass resolution (M/DM) figures of around 1000 for full width at tenth maximum (FWTM) and 500 for full width at thousandth maximum (FW0.1%M) can be achieved with the laser system.

3DAP analysis has been used extensively in materials applications for more than twenty years and has allowed the development of many novel alloy materials in the steel and aluminium industries.

Oxford Nanoscience's 3DAP has already been applied to planar-deposited samples through studies of the thin film multilayered and nanocrystalline materials used in the magnetic data storage industry.

Results obtained from the new system can be seen for the first time at Semicon West (12th to 14th July, Booth 4113, Emerging Technologies Hall, Moscone Centre, San Francisco, California USA).

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