Relaxation of Misfit Induced Strain in Si-Based Heterostructures

摘要

Growing misfitting heteroepitaxial layers tend to deviate from planarity and to form laterally limited structures. Such structures can elastically relax the misfit strain and thus reduce the total free energy of the system. The paper analyses results on ripples and pyramids as they form during solution growth of GeSi solid solution layers on Si(001) substrates. Solution growth occurs under very low driving forces and thus the forming structures exhibit the energetic pathway of the growing system. Evidence is presented that ripples form as an instability phenomenon, but islands nucleate thermally activated. There are some arguments that huts and domes, which form under high driving forces during growth from vapor phase, are of similar nature.