Finite Element Simulation of A Deep-Etched Silicon Spring

Jong Yon Kim, Kevin Huang, and Professor Peter Peumans
Stanford University, USA

We are building large monolithic silicon sensor networks by micromachining silicon substrates. The two-dimensional networks consist of 200 micron diameter silicon islands (nodes) that are connected to adjacent islands via deep-etched spiral ribbons of silicon that are initially rolled up around each of the silicon islands. Upon stretching of the silicon network, the spiral ribbons around each silicon island unroll to yield an area expansion of several orders of magnitude, allowing us build large areas of smart materials using monolithic silicon. The stretching behavior of a single node plays an important role in the proper formation of the network. Due to the complexity of the deformation during the stretching, the Abaqus FEA product suite is used to extract the force vs. Displacement behavior of a single silicon node. Simulation has demonstrated that the node can be successfully stretched to completion without failure. In addition, the understanding of the stretching behavior allows us to design networks to accurately specify the network geometry after stretching.