Origins of the Ductile Regime in Single-Point Diamond Turning of Semiconductors

A germanium surface and the chips produced from a single-point diamond turning process operated in the “ductile regime” have been analyzed by transmission electron microscopy and parallel electron-energy-loss spectroscopy. Lack of fracture damage on the finished surface and continuous chip formation are indicative of a ductile removal process. Periodic thickness variations perpendicular to the machining direction also are observed on these chips and are identified as ductile shear lamellae. The chips consist of an amorphous, elemental germanium matrix containing varying amounts of microcrystalline germanium fragments. The relative orientation of machining marks and crystallographic fragment texture are used to position individual chips with respect to the initial angular cutting zone on the wafer. Chips with high fragment content correlate directly to cutting zones subject to the highest resolved tensile stress on cleavage planes. These findings are explained in the context of a high-pressure metallization (brittle-to-ductile) transformation with ductility limited by the onset of classical brittle fracture.

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

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

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

[4]  J. T. Black.  Shear Front-Lamella Structure in Large Strain Plastic Deformation Processes , 1972 .

[5]  Don A. Lucca,et al.  Effect of Tool Edge Geometry on Energy Dissipation in Ultraprecision Machining , 1993 .

[6]  S. Timothy,et al.  The structure of adiabatic shear bands in metals: A critical review☆ , 1987 .

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

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

[9]  J. T. Black.  On the Fundamental Mechanism of Large Strain Plastic Deformation: Electron Microscopy of Metal Cutting Chips , 1971 .

[10]  W. S. Blackley,et al.  Ductile-regime machining model for diamond turning of brittle materials , 1991 .

[11]  Martin G. Schinker,et al.  Basic Investigations Into The High Speed Processing Of Optical Glasses With Diamond Tools , 1983, Other Conferences.

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

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

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

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

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

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

[18]  D. L. Callahan,et al.  Origins of microplasticity in low-load scratching of silicon , 1994 .