High-quality dual-gate PMOS devices in local overgrowth (LOG)

A new SOI technology is introduced with enhanced device performance and small geometries. The low-impurity crystalline SOI film is produced by VPE local overgrowth (LOG) over an oxide, an important alternative to recrystallised silicon films for 3D-CMOS and SOI circuits. This technology was developed from epitaxial lateral overgrowth (ELO) to allow the use of the substrate as an interconnect layer and to enable access to submerged gates. Surface-channel mobilities are measured to be 165 cm²/V s for PMOS devices built on top of the overgrowth and 160 cm²/V s for devices with a submerged gate. The structures produced by LOG are planar and allow for further stacking of devices.