Mechanical Engineering

Research Aims at Improving Reliability of MEMS Technology, continued

Students and faculty in the Department of Mechanical Engineering are also conducting research to make the commercial realization of such miniature machines possible.

Although miniaturization has long been a scientific and science fiction curiosity, miniature systems have traditionally been limited to electronic components with no moving mechanical parts. However, emerging MEMS technologies contain micro-actuators that provide the capability to grip, move, strike, or even blow. Industrial fabrication facilities exist to manufacture these MEMS, but understanding the reliability of the micro-actuators is still a fledging technological arena.

Under the guidance of CU Professors Ken Gall and Martin L. Dunn, Ph.D. candidate Brian Corff has been charged with understanding the reliability of thermally activated micro-actuators. The actuators are fabricated by depositing a 0.001 millimeter layer of gold onto a 0.001 millimeter layer of silicon. Movement of the micro-actuator is accomplished by heating the layered material system and inducing curvature change via the thermal expansion coefficient mismatch between the gold and silicon. The layered actuators have been shown to perform well for one thermal cycle, but Corff is studying the effect of multiple cycles on the actuation response. For commercial realization of the MEMS actuator, the ability to reliably sustain repeated loading cycles is imperative.

Using specialized electron and interferometric microscopes capable of micrometer and nanometer resolution, Corff will study the behavior of these films as subjected to cyclic temperature changes. He is currently investigating the possible cracking and degradation mechanisms in the film in an initial attempt to understand their reliability.

Although Corff studies the reliability of such devices, he works closely with undergraduate and graduate students in the MEMS design group led by Professor Victor Bright who design small-scale devices. In addition, collaboration with researchers in the electronic packaging group, who have previous experience in the design and reliability of integrated circuits, is critical. Only with coupled interactions between students learning MEMS design and students studying MEMS reliability will widespread commercial use of these products become a reality.