EFFECT OF STRESS SIGN AND FILM THICKNESS ON INTERFACE NUCLEATION OF MISFIT DISLOCATIONS IN STRAINED MULTILAYERS

The strain relaxation mechanism via the homogeneous nucleation of misf it dislocations from the heterointerface in coherently strained layers has been investigated with transmission electron microscopy. It is id entified that the dislocations nucleated from the interface are displa yed in the form of 90-degrees partial, 30-degrees partial, and 60-degr ees perfect dislocations, depending on stress sign and thickness of th e strained layer. The tendency is interpreted in terms of the strain r elaxation efficiency which is given by the ratio of relieved strain en ergy to dislocation line energy.