Origins of microplasticity in low-load scratching of silicon

Microstructural characterization of silicon wafers subjected to controlled low-load scratching with a sharp indenter reveals that considerable plastic deformation occurs prior to the onset of fracture. In particular, a completely ductile response to scratching is observed at or below a Vickers load of 1 g, corresponding to penetration depths of 200 nm or less. This anomalous plasticity arises primarily as a result of a pressure-induced semiconductor-to-metal phase transition (Mott transition). Various levels of subsurface dislocation activity and cracking also contribute to the deformation. The relationships among the phase transformation, dislocation activity, and the onset of fracture are discussed. These findings can be applied to other areas of contact damage demonstrating anomalous plasticity, such as hardness testing and ductile-regime turning.

[1]  D. Tabor,et al.  Indentation hardness and semiconductor–metal transition of germanium and silicon , 1978, Nature.

[2]  M. A. Shahid,et al.  Size effects in abrasion of brittle materials , 1979 .

[4]  J. Schweitz,et al.  Contact Damage in Single‐Crystalline Silicon Investigated by Cross‐Sectional Transmission Electron Microscopy , 1988 .

[5]  J. C. Jamieson,et al.  Crystal Structures at High Pressures of Metallic Modifications of Silicon and Germanium , 1963, Science.

[6]  H. G. Drickamer,et al.  Pressure induced phase transitions in silicon, germanium and some III–V compounds , 1962 .

[7]  Ronald O. Scattergood,et al.  Ductile‐Regime Machining of Germanium and Silicon , 1990 .

[8]  V. I. Trefilov,et al.  Phase transition in diamond‐structure crystals during hardness measurements , 1972 .

[9]  J. Gilman.  Insulator-metal transitions at microindentations , 1992 .

[10]  A. E. Gee,et al.  Transmission electron microscopy of nanomachined silicon crystals , 1994 .

[11]  R. Cook,et al.  Direct Observation and Analysis of Indentation Cracking in Glasses and Ceramics , 1990 .

[12]  O. Shimomura,et al.  Pressure-induced semiconductor-metal transitions in amorphous Si and Ge , 1974 .

[13]  N. Suh,et al.  Plastic deformation of silicon during contact sliding at ambient temperature , 1993, Journal of Materials Science.

[14]  George M. Pharr,et al.  New evidence for a pressure-induced phase transformation during the indentation of silicon , 1991 .

[15]  Kroll,et al.  Amorphization and conductivity of silicon and germanium induced by indentation. , 1988, Physical review letters.

[16]  R. H. Wentorf,et al.  Two New Forms of Silicon , 1963, Science.

[17]  D. Callahan,et al.  The extent of phase transformation in silicon hardness indentations , 1992 .

[18]  Ronald O. Scattergood,et al.  Crystal Orientation Dependence of Machning Damage–A Stress Model , 1990 .

[19]  Surface Defects in Polished Silicon Studied by Cross‐Sectional Transmission Electron Microscopy , 1989 .

[20]  D. Rowcliffe,et al.  Deformation of silicon at low temperatures , 1974 .

[21]  A. E. Gee,et al.  Surface damage in nanomachined silicon , 1992 .

[22]  Spain,et al.  Crystal data for high-pressure phases of silicon. , 1986, Physical review. B, Condensed matter.