Varian Associates

About: Varian Associates is a based out in . It is known for research contribution in the topics: Beam (structure) & Wafer. The organization has 2160 authors who have published 2591 publications receiving 46002 citations.

Electron—Atom Bremsstrahlung

Abstract: In this chapter we discuss electron bremsstrahlung, the radiation of a photon in the scattering of an electron from an atom or ion. We shall focus our attention on incident electrons with kinetic energiesT i in the 100-eV to 10-MeV range (and especially for 1 keV to 1 MeV) and radiated photons in the vacuum ultraviolet, X-ray, and soft γ-ray regimes. Electron bremsstrahlung is only one particular consequence of the general coupling of the electromagnetic field and matter fields. The process is closely related, as we shall see, both to elastic electron scattering and to direct radiative recombination, in which the incident electron does not scatter but is captured by the atom. It is also closely related to pair production. Other charged particles also radiate in scattering, as follows from Maxwell’s equations, and we shall discuss the most closely related case of positron bremsstrahlung. More generally, the electromagnetic coupling to matter fields is responsible for radiative versions of all nonradiative processes, including “inverse bremsstrahlung” processes in which electromagnetic radiation is absorbed rather than emitted.

Compensated scan wave form generator for ion implantation equipment

Abstract: A scan controller for an ion implantation system includes a compensation circuit for generating a scanning signal from a triangle voltage signal. The scanning signal causes an ion beam to be deflected so that, in the variety of geometries describing the orientation of the target in the implantation system, the position of the intersection of the ion beam with the planar target surface changes linearly with time. In one embodiment the scanning signal has the form v(t)=-d -e/(t+c). In other embodiments the compensation circuit approximates the above function by means of polynomials.

Electron beam evaporator having beam spot control

Abstract: An electron beam evaporator employs an electron gun which projects a beam of electrons over an arcuate beam path to a crucible target for heating and evaporating the target material in use. The electron beam passes through the magnetic field supplied by a pair of pole pieces of a beam focus magnet which produces a main field transverse to the direction of the electrons to cause the beam to take the arcuate trajectory. Two pairs of auxiliary pole pieces project inwardly of the main pole pieces to provide a pair of beam focus lenses. One of the magnetic lenses is disposed on the inside of the beam path, whereas the other is disposed on the outside of the beam path to provide beam lateral focusing and defocusing lenses, respectively. The lenses are adjustable, preferably electromagnetically for controlling the beam spot size on the target crucible so that the evaporation characteristics can be optimized for a given beam power. In addition, the magnetic lenses are adjustable, preferably electromagnetically, for sweeping the position of the beam spot longitudinally and/or laterally of the crucible target.