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

Abstract

Recently it was reported that high quality, 10–100 μm thick, single-crystalline Si films were formed 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, therefore, the film stress and defect properties are investigated in detail, and devices made in recrystallized wafers are compared with devices in conventional wafer structures. Stress levels were found to be too low to cause defects, with TEM data suggesting an impurity mechanism (SiO2 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.