CVD Selective Epitaxial Lateral Overgrowth Technique for 3D Stacked SRAM Cell on SOI-Like Silicon Films

Abstract

To integrate three-dimensional (3D) thin-film transistors (TFTs) for the 3D single-crystal Si (S 3 ) static random access memory (SRAM), forming the silicon-on-insulator (SOI)-like single-crystal Si thin films on the oxide layers is essential. The technique to grow selective epitaxial Si films through the seeding contact hole was successfully developed with a single-wafer-type chemical vapor deposition (CVD) and dichlorosilane gas with HCI in H 2 carrier gas. The electrical characteristics of the cell TFTs made on the selective epitaxial growth (SEG) Si films are very close to those of the bulk transistor. Seventy-two Mbit SRAM was successfully developed with this SEG technique and 3D S 3 SRAM cell technology.