The hardness, elastic modulus, and structure of several amorphous carbon films on silicon prepared by cathodic-arc deposition with substrate pulse biasing have been examined using nanoindentation, energy loss spectroscopy ͑EELS͒, and cross-sectional transmission electron microscopy. EELS analysis shows that the highest sp 3 contents ͑85%͒ and densities ͑3.00 g/cm 3 ͒ are achieved at incident ion energies of around 120 eV. The hardness and elastic modulus of the films with the highest sp 3 contents are at least 59 and 400 GPa, respectively. These values are conservative lower estimates due to substrate influences on the nanoindentation measurements. The films are predominantly amorphous with a ϳ20 nm surface layer which is structurally different and softer than the bulk. © 1996 American Institute of Physics. ͓S0003-6951͑96͒01105-6͔A cathodic-arc plasma source equipped with a magnetic macroparticle filter is an efficient tool for depositing highquality thin films of metals, alloys, and compounds. To date, the technique has been employed primarily in laboratory settings, but recent advances have led to large units capable of full-scale commercial production. 1 One material which has received a great deal of attention in cathodic-arc processing is amorphous carbon ͑a-C͒. In addition to being chemically inert, electrically insulating, transparent, and having a low coefficient of friction, cathodic-arc carbon is of interest because of its potential as thin coating material with very high hardness. Amorphous carbon has been deposited from a cathodic arc by various groups. [2][3][4][5][6][7][8] Hardness values ranging from 26 GPa to over 60 GPa have been measured by nanoindentation methods. The difficulties of deriving hardness values for such hard, thin films on softer substrates are well recognized. 9 Nevertheless, the high values reported suggest that a-C with very high hardness can be achieved by cathodic-arc deposition.The key to producing high hardness in amorphous carbon films appears to be in promoting high sp 3 bond content through careful control of the energy of incident ions during deposition. 6,10-14 For cathodic-arc deposition, one way to achieve this is by substrate pulse biasing. 15 Pulse biasing has an important advantage compared to dc bias in that, whereas with dc bias electrical breakdown can result with pulsed biasing the applied voltage can be arbitrarily high ͑the voltage is switched off before the high voltage plasma sheath expands to dangerous distances͒.We have investigated the properties of cathodic-arc carbon as a function of biasing conditions and have found a set of conditions which produces very hard films. Here, we report the hardness and elastic modulus of these films measured by nanoindentation methods and the structure of the films determined by transmission electron microscopy ͑TEM͒ and electron energy loss spectroscopy ͑EELS͒.The carbon films were deposited on silicon substrates using a cathodic-arc plasma source combined with a 90°bent magnetic macroparticle filter. The source and f...

A germanium surface and the chips produced from a singlepoint 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.

The extent of phase transformation occurring in silicon during room-temperature indentation experiments has been examined by transmission electron microscopy of low-load microindents. The results show that the entire hardness impression arises from structural transformation and extrusion of a ductile high pressure phase. In particular, there is no dislocation activity or other mechanism of plastic deformation operating outside the clearly demarcated transformation zone. The observable impression consists of an amorphous transformation zone with an adjacent region of plastically extruded material and a layer of polycrystalline silicon at the near-surface transformation interface.

Periodic line structures with a period of 167 nm and linewidths varying from 35 to 100 nm have been produced on polyimide by direct ablation with a KrF laser using an interferometric technique. Since ablation is a nonlinear process, the resolution can exceed that expected from the wavelength and numerical aperture of the system and the linewidth can be controlled by varying the laser fluence. This externally generated period of 167 nm prevents the spontaneous growth of periodic surface structures due to radiation remnants.