Integration scheme for reducing border region morphology in hybrid orientation technology (HOT) using direct silicon bonded (DSB) substrates

Optimizing carrier mobilities in MOS transistors in CMOS ICs requires forming (100)-oriented silicon regions for NMOS and (110) regions for PMOS. Boundary regions between (100) and (110) regions must be sufficiently narrow to support high gate densities and SRAM cells appropriate for the technology node. This invention provides a method of forming an integrated circuit (IC) substrate containing regions with two different silicon crystal lattice orientations. Starting with a (110) direct silicon bonded (DSB) layer on a (100) substrate, regions in the DSB layer are amorphized and recrystallized on a (100) orientation by solid phase epitaxy (SPE). Lateral templating by the DSB layer is reduced by amorphization of the upper portion of the (110) regions through a partially absorbing amorphization hard mask. Boundary morphology is less than 40 nanometers wide. An integrated circuit formed with the inventive method is also disclosed.