Physical Vapor Deposition

In the early days of microelectronics, physical vapor deposition was simply applied to the evaporation of Al to form the high conductivity connections to transistors. With the ever-increasing complexity of silicon integrated circuits and the development of GaAs circuits, a much wider range of materials must be deposited to fulfill special needs for patterning, electromigration, diffusion barriers, Schottky contacts, air bridges, etc. (Table 1); alloys and compounds must be deposited as well as elemental metals. Sputter deposition has been used increasingly and other specialized techniques have also been applied; reactive evaporation, activated reactive evaporation, ion plating, and cluster ion deposition have been developed to meet special needs. However, evaporative and sputter deposition techniques are still the primary physical vapor deposition methods used for microcircuit fabrication and this review chapter will focus on their similarities and differences as they apply to microcircuit fabrication in both Si and GaAs.