Electron-assisted deposition

Abstract

Previous limitations in utilizing energetic vapor deposition means are addressed through the introduction of a novel means of vapor deposition, namely, an Electron-Assisted Deposition (EAD) process and apparatus. The EAD mode of film growth disclosed herein is generally achieved by, first, forming a magnetic field that possesses field lines that intersect electrically non-grounded first and second surfaces, wherein at least one surface is a workpiece, thereby forming a magnetic trap between first and second surfaces; second, introducing a high flux of electrons axially into the magnetic field existing between the first and second surfaces, so that the electrons form an electron-saturated space-charge in the space adjacent to the substrate, wherein plasma interactions with the substrate are substantially avoided, and modification of film growth processes is provided predominantly by electron—rather than plasma—bombardment.

1 . A process for forming a film on a substrate, comprising:
 a. providing a vacuum chamber;   b. positioning the substrate within the vacuum chamber, the substrate providing a first surface for forming the film thereon, the first surface electrically floating;   c. providing a vapor source within the vacuum chamber, the source for directing vapor toward the substrate, so that the film is formed on the first surface;   d. providing a second surface, the second surface having a negative potential;   e. providing a magnetic field, the magnetic field comprising field lines that intersect the first surface and the second surface, the magnetic field having a central field region corresponding to a relatively high magnetic field; and,   f. providing an electron source adjacent the central region, the electron source providing a sufficiently high flux of electrons into the central field region, so that the electrons expand into the remaining magnetic field in such a way as to decrease average energy of ions bombarding the substrate, relative to an ion energy produced at a lower electron flux.   
     
     
         2 . A sputtering apparatus for forming a film on a substrate, comprising:
 a. a vacuum chamber;   b. a sputtering cathode structure, the cathode structure having a magnetic field means for providing a magnetic field with substantial symmetry about an axis of symmetry, the sputtering cathode structure positioned in the chamber;   c. means for positioning the substrate within the chamber, the substrate providing a first surface for forming the film thereon, the first surface electrically floating, the first surface intersecting the magnetic field of the cathode structure so that an electron trap is formed between the substrate and the magnetron; and,   d. an electron source, the electron source positioned for providing a flux of electrons into the magnetic field substantially along the axis of the magnetic field, the flux sufficiently large to provide an electron-saturated field adjacent to the first surface.   
     
     
         3 . A vapor deposition apparatus utilized in combination with a rotatable cylinder for depositing material onto a substrate, comprising:
 a. a vacuum chamber;   b. a vapor source disposed in the vacuum chamber, the vapor source positioned so as to direct a vapor towards the rotatable cylinder, the vapor containing constituents for forming the material;   c. magnetic field assembly means providing a magnetic field, the magnetic field possessing field lines that intersect the cylindrical surface;   d. an electron source, the electron source positioned for providing a flux of electrons axially into the magnetic field.