Previous investigations have shown both time dependent failures and crack growth under cyclic loading conditions.   Current studies investigate the fatigue mechanisms in polycrystalline and single crystal silicon.

Fatigue tests are performed on 250 mm square, 2 mm thick structure analogous to a fatigue load . frame, specimen, and LVDT (Figure 1).   The electrostatically-actuated, resonant structure allows characterization of fatigue both crack initiation and growth.  This work redefines the notion of "physically small" cracks and crack initiation studies.

Electrostatic actuator

Capacitive deflection transducer

Notched cantilever beam

Figure 1:  Single crystal silicon fatigue crack initiation test structure.