Method of making a selective compositional disordering of a GaAs based heterostructure by the in-diffusion of Au through a single crystal, epitaxially grown Ge film

A method for producing a buried heterostructure device comprising the steps of:

• a.) providing a superlattice substrate comprising at least one planar GaAs layer and at least two AlGaAs layers each in juxtaposition with the GaAs layer;
• b.) epitaxially depositing a single crystal germanium layer on the superlattice substrate;
• c.) depositing a gold layer on the germanium layer;
• d.) imagewise patterning and etching away selected portions of the gold and germanium layers;
• e.) encapsulating the superlattice substrate in a compatible, heat resistant encapsulating material;
• and
• f.) annealing the encapsulated superlattice substrate to attain homogeneous disordering in an uppermost region of the superlattice substrate.