Thickness uniformity of silicon-on-insulator fabricated by plasma immersion ion implantation and ion cut

Plasma immersion ion implantation (PIII) is an economical means to implant a high dose of hydrogen into silicon and when combined with ion cut, has be en demonstrated to be a viable technique to fabricate silicon-on-insulator (SOI), However, its success in the industry hinges on the quality of the SO I wafers produced. One of the most important parameters is the thickness un iformity of the SOI film. We have observed that the thickness variation acr oss a 150-mm wafer follows a pattern in which the transferred silicon film is thickest in the center and thinnest near the edge. Alpha-step and SIMS m easurements indicate that the lateral nonuniformity is caused by the differ ent penetration depths of hydrogen across the wafer. The experimental resul ts can be explained quantitatively by an oblique incidence model.