Showing papers on "Focused ion beam published in 1978"

Growth-orientation of crystals by raster scanning electron beam

Abstract: A method of grain-orienting the crystal structure of a layer of semiconductor material by application of a raster scanning electron beam to a layer of polycrystalline semiconductor material which has been previously formed on a substrate, such as by sputter-plasma film deposition. The method comprises electron beam lithography computer-applied to the crystal growth and orientation of a polycrystalline thin sheet of silicon or other semiconductor material.

Intense ion‐beam neutralization in free space

Abstract: Electron neutralization is a key feature in the propagation of intense ion beams. A one‐dimensional sheath solution is given that demonstrates how electrons are captured by a transient ion beam emerging into a field‐free vacuum. Conditions for space‐charge and current neutralization are discussed. The importance of the electron distribution in determining the minimum spot size of a focused ion beam is considered.

Spatial dose uniformity monitor for electrically scanned ion beam

Abstract: A technique is described for direct and precise monitoring of the spatial dose uniformity of an electrically scanned ion beam. The method employs a two‐dimensional 10×10 array of Faraday cups, individually connected to a current integrator, to measure local dose distribution. It also employs a microprocessor for rapid data processing and topographic data display. The technique is applicable to high quality ion implantation processes as a uniformity monitor with an accuracy of 1%. In addition, a new concept for uniform ion beam scanning is proposed.

Secondary particle collection in ion implantation dose measurement.

Abstract: The measurement of ion implantation doses in the presence of secondary ions and electrons emitted from the target is discussed. A circuit and electrode geometry for obtaining accurate ion beam current measurements in the presence of both positive and negative secondary particles is presented.

Process for channeling ion beams

Abstract: The specification describes a process for minimizing ion scattering and thereby improving resolution in ion beam lithography. First, a substrate coated with a layer of ion beam resist is provided at a chosen spaced distance from an ion beam source. Next, a monocrystalline membrane with a patterned ion absorption region is positioned at a predetermined location between the substrate target and the ion beam source. The patterned ion absorption region may be either an ion absorption mask, such as gold, deposited on the surface of the monocrystalline membrane, or a pattern of ion-damaged regions within the monocrystalline membrane. Finally, a collimated wide area ion beam is passed perpendicular to the surface of the membrane and through crystal lattice channels therein which are exposed by the patterned ion absorption region and which extend perpendicular to the membrane surface. The parallel paths established by the channels in the membrane provide low resistance paths to the passage of ion beams and consequently minimize the angle of deflection of the ions passing from the membrane to the target resist layer.

Ion beam bombardment device

Abstract: In an ion beam apparatus a structure for controlling the surface potential of the target comprising an electron source adjacent to the beam for providing electrons to the beam and means between the target and source for inhibiting rectilinear radiations, i.e., electron and other particle and photon radiations between said source and said target. This prevents heating of the target by the electron source and cross-contamination between the source and the target. A further structure is provided for the measurement of the ion beam current while controlling said surface potential of the target which includes: walls adjacent to and electrically insulated from the target and surrounding the beam whereby the walls and target provide a Faraday Cage, means for introducing variable quantities of electrons into the beam within the Faraday Cage, means for measuring the target current, means for combining and measuring the target and wall currents to provide said ion beam current measurement and means for varying the quantities of introduced electrons to control the target current and thereby the target surface potential.

Reactive Sputter Etching of Thin Films for Pattern Delineation

Abstract: Thin films of several metals, commonly used in integrated circuit fabrication, were reactively sputter-etched in an oxygen atmosphere with a focused ion beam. A decrease in the sputter-etch rate was observed as the partial pressure of oxygen was increased from 1.5 X 10...6 to 1 X 10-4 tort. This decrease was attributed to a buildup of a surface layer of adsorbed oxygen on the target. The partial pressure of oxygen corresponding to this decrease in sputter-etch rate of most metals was calculated on the basis of the thermodynamic properties of the compound formed. There was excellent correlation between calculated and experimental values. For integrated circuit fabrication, a suitable metal can be chosen as a thin-film mask which has a transition pressure lower than those metals on the substrate to be sputter-etched for pattern generation. This transition pressure can be predicted prior to processing.

Ion beam sputter etching and deposition of fluoropolymers

Abstract: Fluoropolymer etching and deposition techniques including thermal evaporation, RF sputtering, plasma polymerization, and ion beam sputtering are reviewed. Etching and deposition mechanism and material characteristics are discussed. Ion beam sputter etch rates for polytetrafluoroethylene (PTFE) were determined as a function of ion energy, current density and ion beam power density. Peel strengths were measured for epoxy bonds to various ion beam sputtered fluoropolymers. Coefficients of static and dynamic friction were measured for fluoropolymers deposited from ion bombarded PTFE.

A technique for the detection of ions in high voltage electron microscopes

Abstract: The application of cellulose nitrate film to the detection of ions in a HVEM is described. The Harwell HVEM, which was used in this study, was found to produce a very low intensity ion beam (≲ 106 ions/cm2/s). The etching properties of the tracks enabled some identification of the ions to be made and it was found that the results could be produced by oxygen ions having an energy spread of 0.3 MeV or by a mono-energetic beam containing ions with atomic numbers between 6 and 12.