Abstract: A vertical bipolar transistor is fabricated in a semiconductor substrate without an epitaxial layer using oxide isolation and ion implantation techniques. Ion implantation energies in the KEV ranges are used to implant selected ions into the substrate to form a collector region and buried collector layer less than 1 micron from the surface of the device, and then to form a base region of opposite conductivity type in the collector layer and an emitter region of the first conductivity type in the base region. Even though ion implantation techniques are used to form all regions, the base and the emitter regions can, if desired, be formed to abut the field oxide used to laterally define the islands of semiconductor material. The field oxide is formed to a thickness of less than 1 micron and typically to a thickness of approximately 0.

Abstract: A semiconductor structure is fabricated using a process involving all ion implantation and using only five masks prior to metallization. A buried contact mask is used to form a buried contact layer (114), an isolation mask is used to form grooves (130a, 130b) in an epitaxial layer of silicon (113), a self-aligned transistor mask is used to form a mask (134a to 134e) to define the areas in which emitters (138a, 140b, 140c) bases (113, 139) and contact regions (140a) are to be formed, a base exclusion mask (135a,b) is provided to exclude certain impurities from being implanted into a region to be formed of one conductivity type, and a second exclusion mask (137a, 137b) is provided to exclude impurities to be implanted in a region of opposite conductivity type from the prohibited regions of the structure.

Abstract: In the bombardment of targets with beams of charged particles, a method for varying and controlling the diameter of such beams by passing the beam through an envelope of conductive material; the envelope is spaced from and coaxial with the beam. A selected D.C. potential is applied to the envelope, and the beam diameter is controlled by changing this applied potential in a direction away from ground potential to increase the beam diameter or by changing the potential in a direction toward ground potential to decrease said beam diameter.

Abstract: In an ion implantation apparatus, a structure for measuring the beam current at the target wherein a Faraday Cage is formed by walls adjacent to and electrically insulated from the target in combination with the target, means for biasing the target at a negative potential, means for biasing the walls at ground potential and means for measuring the target current and the wall current and for combining the two to provide an accurate beam current measurement.

Abstract: In an ion implantation apparatus, means for forming multiple, separate parallel ion beams, each having a predetermined spot diameter, and means for focusing each of said ion beams upon a predetermined chip area of a target wafer whereby multiple chip areas upon the wafer can be simultaneously implanted with prescribed ion dosages.