Stress concentration analysis and fabrication of silicon (100) based ultra-stretchable structures with parylene coating
AuthorsRehman, Mutee Ur
Shaikh, Sohail F.
Conchouso Gonzalez, David
Hussain, Muhammad Mustafa
Rojas, Jhonathan Prieto
KAUST DepartmentComputational Bioscience Research Center (CBRC)
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Integrated Nanotechnology Lab
Online Publication Date2020-10-19
Print Publication Date2020-11
Embargo End Date2022-04-20
Permanent link to this recordhttp://hdl.handle.net/10754/665720
MetadataShow full item record
AbstractResearch in stretchable electronics is helping to revolutionize the current electronic industry, particularly in wearable and bio-integrated devices. Cost-effectiveness and easy manufacturing are key factors that contribute to shaping the fate of such technologies. In this work, we present a fabrication method for a novel ultra-stretchable, serpentine-arm spiral (SAS) that was built using a low-cost, standard bulk silicon (100) wafer. However, structural defects that often appear during patterning processes, can lead to stress concentration and structural failure at these sites upon stretching. Parylene coating of the structures is proposed to minimize this stress concentration and improve structure's robustness. Finite element analysis (FEA) was performed to demonstrate the concentration of stress at these defective sites with 2 sizes (0.1μm and 1μm) and at different locations along the arms. Results show that SAS structures reach up to ∼80% stress reduction at the defective location compared to straight-arm spirals, while the parylene-coating helps to reduce it up to ∼60% further. On the other hand, fabricated uncoated, SAS structures reached up to ∼600% prescribed strain before fracture, while parylene-coating improves this maximum admissible strain in ∼50%. Additionally, a cyclic tensile test was then performed on the fabricated structures, uncoated and parylene-coated, for over 3000 cycles without fracture. The results observed on coated structures greatly improve the mechanical reliance of such brittle structures, which could be extended to other stretchable configurations.
CitationRehman, M. U., Babatain, W., Shaikh, S. F., Conchouso, D., Qaiser, N., Hussain, M. M., & Rojas, J. P. (2020). Stress concentration analysis and fabrication of silicon (100) based ultra-stretchable structures with parylene coating. Extreme Mechanics Letters, 101052. doi:10.1016/j.eml.2020.101052
SponsorsThe authors would like to acknowledge the support provided by the Deanship of Scientific Research (DSR) at King Fahd University of Petroleum & Minerals (KFUPM), Saudi Arabia for funding this work through projects No. IN161020 and No. KAUST001.
JournalExtreme Mechanics Letters