Single-Crystal Islands (SCI) for Monolithic 3-D and Back-End-of-Line FinFET Circuits

A single-crystal islands (SCI) technique using low thermal budget pulse laser process is proposed and demonstrated to fabricate single-crystal silicon islands over amorphous dielectric for monolithic 3-D and back-end-of-line (BEOL) FinFET circuits. By laser recrystallizing mask-defined a-Si islands encapsulated with conformal silicon nitride film, designed single-crystal Si islands can be obtained. The single crystallinity of the island are verified with SECCO Etch, high-resolution electron microscopy (HREM), transmission electron microscopy (TEM), and electron backside scattering (EBSD). About 40 nm FinFETs were successfully fabricated in the SCI Si islands and shown to exhibit excellent electrical performance and low variability that are compatible with the FinFETs fabricated on commercial silicon-on-insulator (SOI) wafer.