Large area recrystallization of thick polysilicon films for low cost partial SOI power devices

This paper focuses on the process fabrication of a partial silicon-on-insulator (SOI) substrate for mixed power integration (low and high voltage devices on the same chip) at low cost. More specifically, such application would require a silicon substrate having localized thick SOI patterns associated with lateral isolation for control modules and bulk areas for power devices. The Lateral Epitaxial Growth over Oxide process (LEGO) based on fusion and recrystallization of polysilicon patterns, is a solution to obtain such a substrate at low cost and with a good SOI layer crystalline quality. A brief description of LEGO together with experimental results of LEGO process optimisation are presented.