Synthesis of SOI Materials by Plasma Immersion Ion Implantation

As the dimensions of integrated circuits shrink towards the deep sub-micrometer regime, silicon-on-insulator is regarded to be more favorable than silicon substrates. The biggest drawback of SOI is cost which will become more critical for next generation 300-nm silicon wafers. Plasma immersion ion implantation (PIII) provides a viable alternative for the fabrication of SOI wafers as the processing time is very short and independent of wafer size. PIII is being employed to synthesize two types of SOI materials, SPIMOX (Separation by Plasma IMplantation of OXygen)and bonded SOI. In SPIMOX fabrication, both oxygen and water plasmas have been attempted and the results indicate that a discrete buried oxide layer can indeed be formed. In the case of wafer bonding, PIII is utilized for smart-cutting, a process in which implanted hydrogen or helium causes the bonded wafer to crack along the plane thereby making one side of the wafer recyclable. This article reviews the work done and current stauts of SOI fabrication by PIII.