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Pulsed direct current power supply configurations for generating plasmas

  • US 5,917,286 A
  • Filed: 05/08/1996
  • Issued: 06/29/1999
  • Est. Priority Date: 05/08/1996
  • Status: Expired due to Term
First Claim
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1. A power supply for generating a pulsed direct current having alternating polarities to be applied to a plasma chamber to generate plasmas comprising:

  • a power source that generates a substantially constant supply of said direct current;

    current connections for delivering said pulsed direct current to said plasma chamber;

    current reversing switches having at least two predetermined positions, said current reversing switches coupled to said power source and said current connections that cause said substantially constant supply of said direct current to flow in a first direction through said current connections whenever said current reversing switches are set in a first predetermined position, and in a second direction through said current connections whenever said current reversing switches are set in a second predetermined position;

    wherein said current reversing switches comprise a first pair of switches connected in series across said power source and connected to a first current connection at a point where said first pair of switches are connected in series, and a second pair of switches connected in series across said power source and connected to a second current connection at a point where said second pair of switches are connected in series; and

    at least one additional pair of switches connected in series across said power source and connected to an additional current connection at a point where said additional pair of switches are connected in series.

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