Elimination of Subboundaries in 0.5-µm-Thick Si-on-Insulator Films Produced by ZMR

When Si-on-insulator films 0.3 to 0.5 µm thick are recrystallized by zone melting under the usual conditions, the defect trails within grains are subboundaries. We report that the use of an entrainment pattern, consisting of a grating of carbonized photoresist on top of the SiO2 encapsulating layer, can lead to the replacement of subboundaries by defect trails that are spaced dislocation clusters or discrete threading dislocations. Such defects are expected to be less detrimental to submicrometer MOSFET circuits than subboundaries.