Image Number 5 for United States Patent #7893424.
The semiconductor layer structure includes a superlattice composed of stacked layers of III-V compound semiconductors of a first and at least one second type. Adjacent layers of different types in the superlattice differ in composition with respect to at least one element, at least two layers of the same type have a different content of the at least one element, the content of the at least one element is graded within a layer of the superlattice, and the layers of the superlattice contain dopants in predefined concentrations, with the superlattice comprising layers that are doped with different dopants. In this way, the electrical, optical and epitaxial properties of the superlattice can be adapted in the best possible manner to given requirements, particularly epitaxial constraints.
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