Abstract: A method and apparatus for cleaning contaminated surfaces, especially semiconductor wafers, using energetic cluster beams is disclosed. In this system, charged beams consisting of microdroplets or clusters having a prescribed composition, velocity, energy and size are directed onto a target substrate dislodging contaminant material. The charged, high energy cluster beams are formed by electrostatically atomizing a conductive fluid fed pneumatically to the tip of one or more capillary-like-emitters.

Abstract: An improved ion detection system and method for detection of low or high mass ions. A target having a low work function, photoemissive surface layer is employed to fragment the incident ions and produce secondary negative ions and electrons. The target surface preferably is formed of a thin layer of an alkali antimonide compound, bialkali antimonide compound, multi-alkali antimonide compound, cesiated III - V semiconductor compound, or other photoemissive material having a relatively low band gap energy and electron affinity. Additionally, the photoemissive material should have a low thermionic emission level at room temperature to reduce noise levels in the detector. The secondary ions and electrons may be detected by a conventional electron multiplier detector. The potential difference between the target surface and electron multiplier detector is chosen to accelerate the secondary ions and electrons to the electron multiplier detector with an energy corresponding to high detection efficiency.

Abstract: An improved ion detection system and method for detection of low or high mass ions having high electron affinity constituent atoms or molecules. A target with a low work function target surface is employed to fragment the incident ions and produce secondary negative ions and electrons. A cesium or barium oxide source is employed to optimally provide a monolayer of cesium or barium oxide on the target surface of a molybdenum or tungsten target. The secondary ions and electrons are detected by a conventional electron multiplier detector. The potential difference between the target surface and electron multiplier detector is chosen to accelerate the secondary ions and electrons to the electron multiplier detector with an energy corresponding to high detection efficiency.

Abstract: A process for producing ultrafine particles includes the steps of providing a consumable electrode having a rod or wire configuration, melting the tip of the electrode by means of electron bombardment, and applying an intense electric field to the molten tip to generate a beam of charged droplets. By heating the tip of the rod but avoiding melting of the tip and subsequently applying an electric field to the heated tip, an ion beam may be generated.

Abstract: Impure silicon, in relatively thin sheet form is purified by heating it in the presence of a strong electric field to ionize and remove impurity elements. Ion bombardment may be used to dislodge impurities accumulating on the surface of the sheet.

Abstract: An improved system for generating an ion beam comprises a nozzle through which a gas to be ionized is fed, and a ring electrode encircling the tip of the nozzle. High positive potential and negative potential are applied to the nozzle and ring electrode, respectively, to create a high intensity electric field. The gas atoms passing through the capillary nozzle are ionized, and the ions so created are accelerated in a direction forwardly from the nozzle by the field. The current level or "brightness" of the ion beam so generated may be controlled by varying the pressure of the gas supplied to the nozzle, or the electrical potential difference applied between the nozzle and ring electrode.

Abstract: Amorphous or microcrystalline alloy powder is prepared by the rapid quenching of ultrafine metallic spheroids generated from the molten metal state. The molten metal droplets are formed when an intense electric field (10.sup.5 V/cm) is applied to the surface of liquid metal held in a suitable container. The interactions between the intense electric field and liquid surface tension disrupts the metal surface, resulting in a beam of positively charged droplets. The liquid metal spheres generated by this electrohydrodynamic process are subsequently cooled by radiative heat transfer. Rapid cooling of the droplets may be accomplished by heat transfer to a low pressure gas by free molecular heat conductivity. Quenching rates exceeding 10.sup.6 .degree.K./sec are possible using this technique. Thin film coatings are prepared by electrohydrodynamically spraying a beam of charged droplets against a target (substrate). The target can be electrically controlled to effect the charged particles impact.

Abstract: Apparatus and method for separating materials, particularly isotopes of heavy metals. An electrohydrodynamic source of positive ions directed in a beam to a transverse magnetic field which deflects the ions along paths which carry the different mass ions to different collectors. An ion source incorporating a container for molten material, a pressure system for delivering the liquid material to a capillary tube, and a high voltage power supply providing an intense electrostatic field at the tube end for producing ions by field emission.