This disclosure provides systems, methods, and apparatus related to blocking macroparticles in deposition processes utilizing plasmas. In one aspect, an apparatus includes a cathode, a substrate holder, a first magnet, a second magnet, and a structure. The cathode is configured to generate a plasma. The substrate holder is configured to hold a substrate. The first magnet is disposed proximate a first side of the cathode. The second magnet is disposed proximate a second side of the substrate holder. A magnetic field exists between the first magnet and the second magnet and a flow of the plasma substantially follows the magnetic field. The structure is disposed between the second side of the cathode and the first side of the substrate holder and is positioned proximate a region where the magnetic field between the first magnet and the second magnet is weak.
STATEMENT OF GOVERNMENT SUPPORT
 This invention was made with government support under Contract No. DE-AC02-05CH11231 awarded by the U.S. Department of Energy. The government has certain rights in this invention.