The present invention can provide ion implanter devices including an arc chamber including at least a first inner region and a second inner region, an electron emitting device disposed in the arc chamber adjacent the first inner region and adapted to emit electrons, an electron returning device disposed in the arc chamber adjacent the second inner region and adapted to return at least some of the electrons emitted from the electron emitting device into the second inner region; and an electric field and magnetic field generating device adapted to provide a magnetic field to the arc chamber, wherein at least one inner wall of the arc chamber has a convex surface.