The natural of residual stress, defects, and device characteristics for thick single crystalline Si films on oxidized Si wafers.

Recently we reported forming high quality, 10 to 100micron thick, single-crystalline Si films on oxidized single-crystalline Si wafers by the Lateral Epitaxial Growth over Oxide (LEGO) process. Although this recrystallization process is reliable and reproducible, periodic regions of dislocations in the otherwise relatively dislocation-free Si film were not well understood. In this paper we therefore investigated the film stress and defect properties in detail, and then compared devices made in recrystallized wafers versus conventional wafer structures. We found stress levels too low to cause defects, with TEM data suggesting an impurity mechanism (SiO sub 2 precipitation) for small dislocation loops, and slight crystalline misorientation for long dislocation lines in the periodic, defective areas. Device results confirmed that LEGO is a viable alternative to the Dielectric Isolation (DI) technology.