12° design rule for single crystal silicon curved beam compliant mechanisms with large deformation

We present a new 12° design rule to enhance the reliability of single crystal silicon (SCS) compliant mechanism with large deformation. This rule defines a suitable structure orientation on an SCS wafer and avoids failure of stress induced crystal slip on curved compliant beams. Our rule considers the crystalline directional properties, such as Young´s Modulus and fracture strength, of SCS. We fabricated a rotational mirror as demonstrator which was displaced by a piezoelectric actuator. Obeying to the 12° design rule we achieved a 100% larger rotational angle at the mirror section than in case of arbitrary orientation.