Enhancement of the machinability of silicon by hydrogen ion implantation for ultra-precision micro-cutting

This paper presents the implementation method of surface modification by hydrogen ion implantation in silicon on the enhancement of machinability of silicon by facilitating the brittle-to-ductile transition. The distribution of the implanted hydrogen ions and induced displacements in the sub-surface of silicon wafer is visualised through modelling. The micro-cutting experiments are conducted on ultra-precision raster milling to verify the enhancement effect on the machinability of silicon.Department of Industrial and Systems Engineering2013-2014 > Academic research: refereed > Publication in refereed journa

Effect of implanted fluorine on MOS structures with sputtered SiO₂ insulator

Fluorine was introduced by ion implantation into MOS structures with sputtered oxide. After annealing, its effects on the high-frequency C-V curve and Fowler-Nordheim tunnelling barrier height were studied. An increase of acceptor dopant concentration in the substrate was observed due to the fluorine implantation. The presence of fluorine increased the Fowler-Nordheim tunnelling barrier height for electron injection from both metal and silicon. The role of fluorine is explained by a physical model similar to that used by Ma [4], where fluorine is assumed to bond with trivalent silicon trap centres in the sputtered oxide

Low temperature doping of poly-SiGe films with boron by co-sputtering

SiGe films were boron doped by co-sputtering from Si-Ge-B target. Crystallization of amorphous Sice films and dopant activation were realized by furnace annealing at 550 and 570 degrees C, temperatures which are suitable for processing on Coming glass 7059. The composition of boron doped films and their crystallization process were analyzed by Rutherford backscattering spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Electrical properties of the films were characterized in Van der Pauw structure and by spreading resistance. Boron concentration incorporated in the films was in the range of 2 to 10\% and the activated carrier concentration was between 6 x 10(18)-6 x 10(20) cm(-3). Very low resistivity of SiGe boron doped films in the range of 3-5 m Omega cm was obtained. It was also found that increased boron concentration leads to retarded crystallization of SiGe films. (C) 2000 Elsevier Science S.A. All rights reserved

SiGe-Si junctions with boron-doped SiGe films deposited by co-sputtering

SiGe films were deposited and in situ doped by RF-magnetron co-sputtering on oxidized and bare silicon wafers. Post-deposition annealing was done in the temperature range from 580 to 950 degrees C. Structural and compositional characterization was performed by XRD, Raman, TEM and XPS analysis. Electrical properties were obtained by four-point probe measurements on SiGe films, and current-voltage measurements on SiGe(p(+))-Si(n) diode structures. Excellent rectifying properties of SiGe-Si diodes were observed, and the conduction current mechanisms at different annealing temperatures were discussed. (c) 2006 Elsevier Ltd. All rights reserved

Solid state reaction of ruthenium with 6H-SiC under vacuum annealing and the impact on the electrical performance of its Schottky contact for high temperature operating SiC-based diodes

Thin films and Schottky diodes dots of ruthenium (Ru) on bulk-grown n-type-6-hexagonal-silicon carbide (6H-SiC) were annealed isochronally in a vacuum furnace at temperatures ranging from 500-1,000 °C. Rutherford backscattering spectroscopy analysis of the thin films showed formation of ruthenium silicide (Ru2Si3) at 800 °C, while diffusion of Ru into 6H-SiC commenced at 800 °C. Raman analysis of the thin films annealed at 1,000 °C showed clear D and G carbon peaks which was evidence of formation of graphite. At this annealing temperature, the Schottky contact was observed to convert to an ohmic contact, as evidenced by the linearity of current-voltage characteristic, thereby, rendering the diode unusable. The transformation from Schottky contact to ohmic contact is attributed to graphite formation at the interface