a1 EMPA Thun, Swiss Federal Institute for Materials Testing and Research, Laboratory for Materials Technology, 3602 Thun, Switzerland
a2 Advanced Photonics Laboratory, Swiss Federal Institute of Technology EPFL, 1015 Lausanne, Switzerland
a3 EMPA Thun, Swiss Federal Institute for Materials Testing and Research, Laboratory for Materials Technology, 3602 Thun, Switzerland
A novel method for in situ scanning electron microscope (SEM) micro-compression tests is presented. The direct SEM observation during the instrumented compression testing allows for very efficient positioning and assessment of the failure mechanism. Compression tests on micromachined Si pillars with volumes down to 2 μm3 are performed inside the SEM, and the results demonstrate the potential of the method. In situ observation shows that small diameter pillars tend to buckle while larger ones tend to crack before failure. Compressive strength increases with decreasing pillar diameter and reaches almost 9 GPa for submicrometer diameter pillars. This result is in agreement with earlier bending experiments on Si. Difficulties associated with precise strain measurements are discussed.
(Received March 14 2006)
(Accepted December 18 2006)