Effect of Surface Morphology and Crystal Orientations on Tensile Fracture Property of (110) Single Crystal Silicon

Abstract

We report the effects of surface damage and crystal orientation on fracture strength of single crystal silicon (SCS) by means of tensile test using electrostatic-force grip. The specimens of three major crystal orientations fabricated from (110) SOI wafer were characterized with different surface morphologies prepared by the specimen patterning process.Our specimen patterning process was composed of Bosch process and wet etching process for surface residue removal.We changed processing time and sequence of the two processes to get different surface morphologies. As result of uni-axial tensile test of 9 types of specimens (length: 120 μm, width: 5 μm, thickness: 5 μm), i.e. specimens of 3 crystal orientations with 3 different surface morphologies, improvement of surface morphology doubled average tensile strength: e.g. <110> strength varied from 1.8 GPa to 3.6 GPa, while average tensile strength difference among crystal orientations was less than 20 % on each fabrication conditions. The fracture surfaces mainly consisted of (111) plane.We found tensile fracture characteristics of 3 crystal orientations: in <100> specimens the fracture origin location changed by the fabrication conditions, while <110> and <111> specimens respectively showed quantitative relationships between surface morphology and tensile strength common to different fabrication conditions. These results are beneficial for tensile strength prediction from surface morphology.

Crystal orientation-dependent fatigue characteristics in micrometer-sized single-crystal silicon

“…From this observation, the {111} plane was considered as the primary fracture surface in our specimens at RT. This result is consistent with the results of tensile tests [8][9][10] and general fracture behavior in brittle semiconductors with a diamond structure 7 .…”

“…In other words, it is still unclear regarding which stress component should be responsible for fracture: principal stress, normal stress or shear stress on a unique crystal plane. Through orientationdependent micro-tensile tests on SCS, the {111} plane has been observed as a primary cleavage surface at RT [8][9][10] . Normal stress on the {111} plane has been proposed as a good fracture criterion from the statistical analysis of micro-tensile tests 9 .…”

Fracture behavior of single crystal silicon with thermal oxide layer

“…4. More than half of the samples fractured from the pit on the top corner as similar as our previous report [11], which may formed by a jaggy of the photoresist pattern for an etching mask. But other fracture origins were observed; either top, side, or bottom surfaces.…”

Effect of crystallographic orientation on tensile fractures of (100) and (110) silicon microstructures fabricated from silicon‐on‐insulator wafers

“…While accurate estimations of strength are currently unavailable, our experimental results indicate that the depth of surface defects is a Fig. 8 Fracture shapes of the specimens a Plan views of (100) specimens (type P) b Plan views of (110) specimens (type B) [14] c Schematics of fractured shapes Fig. 9 Surface morphology of bottom surface of (100) silicon Pit-like defects are scattered on the bottom surface Fig.…”

“…The specimen patterning process included a surface treatment process with an isotropic silicon etching solution and the Bosch process. The (110) specimens, called types A and B when measured in our previous report [14], were prepared so that two different surface morphologies were present, as a result of different surface treatment time of 15 and 5 s for types A and B, respectively. The (100) specimens used in the current research, called type P, were fabricated under the same fabrication conditions as for type B.…”