Measuring internal stresses with the perfect tip
Dübendorf, St. Gallen und Thun, 21.5.2007 - We expect them as a matter of course, as self-evident as sunshine in summer – more powerful computers, cell phones with yet more functions, even smaller MP3 players, and so on. At the heart of each of these high tech devices sits a silicon chip bearing minute electronic circuits. To monitor the quality of such chips, optical methods such as Raman spectroscopy are used. Empa materials expert Johann Michler and his team have now managed to make significant improvements to this spectroscopic technique. With colleagues from the Max Planck Institute for Microstructure Physics in Halle, Germany, the Empa researchers constructed probe tips out of silicon nanowires which improve the precision of the Raman method by a factor of up to a hundred. This allows changes at the molecular level – such as those on a microchip - to be observed.