Abstract: A method 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. The high extraction field necessary for atomization and formation of charged clusters, on the order 10.sup.5 volts/cm or greater, is provided by applying a potential difference between the emitters and a counterelectrode. Since the charged clusters, typically 0.01 to 0.1 micron in diameter, are multiply charged, acceleration through 10 kV or more results in large substrate impact energies greater than 0.5 million electronvolts.

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. The high extraction field necessary for atomization and formation of charged clusters, on the order 10.sup.5 volts/cm or greater, is provided by applying a potential difference between the emitters and a counterelectrode. Since the charged clusters, typically 0.01 to 0.1 micron in diameter, are multiply charged, acceleration through 10 kV or more results in large substrate impact energies greater than 0.5 million electronvolts.

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: 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.