In recent times, special merits of negative ion beams have been recognized in the context of novel materials science applications, and there is a plenty of room for further growth of the field. Various kinds of negative ion sources are currently available. Compact surface-plasma type sources, namely, Penning, planotron and semi-planotron sources, are discussed with special emphasis on the merits of these sources for applications in the area of microlithography, ion microscopy, and surface modifications. The potential of these sources for high-current applications, such as spallation neutron source, is also discussed. ©1998 American Institute of Physics.