Experimental Analysis of River Patterns in Silicon Brittle Fractures

(Received 17 January 1995, received in final form 27 February 1995, accepted 7 March 1995)

Abstract
During propagation of brittle cracks in silicon single crystal, steps parallel to the direction of the crack and separated by terraces, are often created. As the crack further propagates, these steps gradually coalesce. This produces the characteristic surface morphology usually identified as a river pattern. An experimental analysis of these river patterns appearing during fractures of silicon single crystals at room temperature is presented. The coalescence of the steps and the coarsening of the terrace widths reveal an effective interaction between the propagating steps. With an interaction between steps supposed to be determined by the size of the terraces, the observed river patterns are numerically reproduced.