GROWTH OF CU3SI FROM CUCL VAPOR-DEPOSITION ON SI(100) ORIENTED WAFERS

The process of nucleation and growth of Cu3Si from the reduction of CuCl with Si(100) oriented wafers has been studied in the gaseous phase using scanning electron microscopy. The lateral growth of Cu3Si nuclei takes place only towards Si{leftwards paired arrows}100{left arrow, hooked} directions for nuclei of sizes less than 5 μm. In that case, Cu3Si nuclei are octahedral-shaped. Above 5 μm, the growth of Cu3Si is effected moreover towards Si{leftwards paired arrows}100{left arrow, hooked} directions, imparting to the nuclei formed in open system a nearly octogonal base plane. On the other hand nuclei generated in closed system are more and more star-shaped with increasing reaction times. Their maximal size is about five times greater than that observed in open system. The nucleation of Cu3Si in open system is almost instantaneous from a reaction time of 2 h at temperatures ranging from 275 to 325°C. © 1990.