Stable ground anode aperture for thin film processing

A physical deposition chamber for forming a film on substrates, comprising:

• a vacuum enclosure having sidewall, ceiling and floor;
• a substrates carrier positioned over the floor and supporting at least one substrate;
• a sputtering cathode positioned within the vacuum enclosure and including a sputtering target and a magnetron, the sputtering target maintaining a plasma that sputters adsorbate particles from the sputtering target at multiple angles towards the at least one substrate;
• a gas injector delivering gas to the plasma;
• an anode aperture shield attached to the sidewall at a level above the substrate carrier and below the sputtering cathode, the anode aperture shield being grounded and defining an aperture for admittance of adsorbate particles approaching the at least one substrate at angles smaller than a preset angle from vertical to the substrate.