COHERENCY STRAIN AS AN ATHERMAL STRENGTHENING MECHANISM

We have grown homogeneous thick layers of InGaAs on InP with 0.2% stra in and also coherently strained superlattices with the same net strain . The thick layers can relax by plastic deformation during growth, and relax further under annealing at higher temperatures. In contrast, su perlattices with alternating coherency strains remain fully strained e ven under annealing at 900 degrees C, above 85% of their estimated mel ting points. We conclude that coherency strain can be a powerful stren gthening mechanism which is athermal and hence useful for high-tempera ture structural materials.