Oriented Aluminum Films on Silicon by Direct Ion Beam Deposition

Abstract

The formation of metal films on Si at low temperatures is of fundamental interest in thin film physics, as well as a key step in the processing of integrated circuits for microelectronics. If grain size and uniformity could be controlled in the Al metallization used in semiconductor manufacturing, the reliability of such conductors, particularly during thermal cycling, could be greatly improved. One possible way to achieve such control is through the introduction of energy in the form of energetic ions during film growth. [1] The Al on Si system is especially interesting, not only because Al is presently the conductor of choice for microelectronics fabrication, but also because the system exhibits unusual interface properties. [2] It has been demonstrated that oriented crystalline Al films can be grown on Si( 111) and Si(100) surfaces at room temperature by the technique of ionized cluster beam deposition (ICB), even though there is a large mismatch in the size of the respective lattices (25%). [3,4] It is important to determine whether similar oriented growth can be achieved by other thin film deposition techniques and to understand the significant deposition parameters. In this paper we will study the formation of oriented Al films on Si by direct deposition from a low-energy mass-analyzed ion beam.