Fabrication and application of relaxed buffer layers

Principles involved in the fabrication of compositionally graded, relaxed buffer layers with low threading dislocation densities are discussed. It is recognized that two key elements are important in controlling the kinetics of lattice relaxation. A bulk strain dependent surface roughness study is described as an application using the relaxed buffers, where an asymmetric behavior of the surface roughness with respect to the sign of strain is observed and explained as a result of strain induced changes in surface step energies.