Browse Prior Art Database

Magnetron Ion/Deposition Source

IP.com Disclosure Number: IPCOM000037226D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+3]

Abstract

The present deposition system consists of a combination of three separate devices; a magnetron, an ion source, and a hollow cathode. The system utilizes the hollow cathode enhanced magnetron effect for the purpose of producing an intense, broad beam ion source which can also be used for sputter-deposition purposes. A schematic of the invention is shown in the figure. In this figure, the ion source is contained within enclosure 51, which, similar to the case of the prior- art ion sources, is biased positively by power supply 50. This power supply will determine the ion energy of the ions emitted from the source. Also similar to prior-art sources, an array of aligned apertures is present at the front of the source.

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Magnetron Ion/Deposition Source

The present deposition system consists of a combination of three separate devices; a magnetron, an ion source, and a hollow cathode. The system utilizes the hollow cathode enhanced magnetron effect for the purpose of producing an intense, broad beam ion source which can also be used for sputter-deposition purposes. A schematic of the invention is shown in the figure. In this figure, the ion source is contained within enclosure 51, which, similar to the case of the prior- art ion sources, is biased positively by power supply 50. This power supply will determine the ion energy of the ions emitted from the source. Also similar to prior-art sources, an array of aligned apertures is present at the front of the source. The screen grid 36 is either in electrical contact with the enclosure 51 or can be biased negative of the enclosure by power supply 62. The accelerator grid 38 is biased negative with respect to ground by power supply 52. Within the ion source enclosure 51, a cathode plate 57 is mounted. This plate is biased negative with respect to the enclosure 51 by power supply 60, which will determine the energy of ion bombardment of the cathode plate 54. The cathode plate is backed by an array of magnets 54 which are arranged to give a largely transverse magnetic field 53 at the surface of the cathode plate. A hollow cathode electron emitter 56 is placed near the edge of the cathode plate 57 such that electrons emitted from the cathode couple into the field lines 53. This hollow cathode is biased negative with respect to the enclosure by power supply 58. All supplies in this device are DC, although pulsed (or AC) operation is entirely possible and should not be discounted. An ionizable gas (such as argon) can enter the source 64 through the hollow cathode 56. The hollow cathode discharge is initiated by standard means and a plasma can be formed inside the enclosure 51 by biasing the hollow cathode negative with supply 58. This discharge is strongly coupled with the magnetic field. When a negative potential is applied to the cathode plate 57 with power supply 60, ion current is drawn from the plasma to this cathode. The plasma density, and hence the ion current to the cathode plate, will be dependent on the potential of the cathode plate and the amount of emission from the hollow cathode. The plasma in the enclosure 51 causes an electric field perpendicular to the cathode plate surface. This, in conjunction with the strong transverse magnetic field, causes an ExB drift of the electrons. The ExB drift current is perpendicular to the surface at positions 61 and 62. This circular drift current is characteristic of all magnetron-like devices and provides a very dense plasma due to the high ionization probability of the trapped, drifting electrons.

The dense plasma is not bound by the magnetic field, and fills the enclosure
51. As ions pass through the apertures of the screen grid 36, they are attracted and...