The past decade has witnessed the establishment of a new field of technology concerned with the manufacture of microscopic sensors and actuators, known as Micro-Electro-Mechanical-Systems (MEMS). The field of MEMS is based on the use of integrated circuit fabrication techniques to create devices capable of acting as mechanical, electrical, and chemical transducers for applications in areas such as the automotive and medical industries. As these structures continue to move from laboratory curiosities to commercial products, it will become necessary to predict the life-span of these devices. Unfortunately, such predictions are currently difficult to make because little work has been done to characterize the fracture of the thin film materials used to make up the mechanical elements of MEMS devices. The goal of this project is to amend this situation by designing a microdevice capable of measuring the strain at fracture of the thin films used in MEMS, and applying this test device to characterize the fracture or polycrystalline silicon (polysilicon), a material commonly used in MEMS devices. This report describes a fracture test structure incorporating bending cantilever beams to determine fracture strain, and its use to study the effects of hydrofluoric acid (HF) on the fracture strength of polycrystalline silicon.
May 31, 1995
Jones, P. T. (1995). A Micro-electro-mechanical Systems (MEMS) Device to Measure the Fracture Strain of Polycrystalline Silicon. United States: University of California, Berkeley.