Strain enhancement in Si induced by direct bonding of a LaAlO3 film to a Si substrate

The depth profiles of lattice strain near the interface regions of LaAlO₃/Si and the SiO₂ interfacial layer/Si were investigated by the ion channeling technique using high-resolution Rutherford backscattering spectroscopy (HRBS). In the case of the LaAlO₃/Si stack, horizontal tensile strain in the Si near the interface was clearly observed. However, this strain was relaxed by formation of the interfacial layer through annealing in an oxygen ambient. These results suggest that the strain in Si induced by a dielectric strongly depends on the material in contact with Si.