Advanced Study of Microfabricated Stretchable Silicon-based Structures

Current silicon-based electronics are brittle and rigid, which pose an enormous challenge for novel, rising technologies, such as wearable electronics, bio-integrated systems, soft-robotics, among many others. Such applications not only demand for high electrical performance, but also come with new mechanical demands. In other words, the electronics must also display high compliance with asymmetric shapes and surfaces, as well as mechanical adaptability and mobile behavior. Many approaches have been explored to close the gap between conventional rigid electronics with the new mechanical demands. An interesting methodology that tries to address this issue is the use of novel geometries and structural modifications, which can actually transform conventionally rigid materials (such silicon) into flexible and even stretchable platforms. Such is the case of spirals, serpentines, fractals, among others. Previously, I have demonstrated the use of innovative Si-based spirals, as flexible and stretchable platforms. Nevertheless, the arms of the spirals were fragile and prompt to fracture. Any small defect during fabrication was leading to weak points where fracture could be originated. During the past several months I have been working on the mechanical modelling and optimization of these structures to drastically improve this issue. Based on the concept of fractals, commonly found in nature, where same structures are found within structures, I envisioned that large improvement could be achieved by designing compound structures with the same fractal concept. Hence, I designed a spiral with serpentine arms, which have been found to be much more mechanically robust. So far we have been able to demonstrate through Finite Element Analysis (FEA) that the experienced stress by our novel simulated structures can be reduced by ~70% compared with the simpler, original design. As a subsequent important stage to demonstrate the effectiveness of the suggested structures, Im proposing the fabrication and mechanical characterization of such novel structures as means for validation of our simulation and modelling results. The compiled results from this study will be then summarized in a journal paper and later on, the structures could be used to build stretchable, high performance electronic systems, an important step to demonstrate the effectiveness of structural optimization of micrometric silicon-based structures.