Heteroepitaxial growth of sixfold symmetric osmium on Si (111)and Si (100)

Growing sixfold symmetric osmium (Os) epitaxial films with suitable buffer layers was developed. Using a Cu buffer layer, the lattice mismatch between Os (0002) and Si (100) was significantly reduced from > 30 % to ∼ 7 % to grow Os films with twin relationships and weak sixfold symmetries. On the other hand, the Cu ∕ Au buffer layer was selected to form a fcc (111) surface mesh on H-Si (111)- 1 × 1 , and therefore sixfold symmetric Os films were grown due to the lower lattice mismatch. Such growth properties may be applied in the high density magnetic random access memory manufacturing processes to connect the magnetic tunnel junction growth and Cu metal line directly.