Method for producing a spatially periodic semiconductor layer structure

In a method for producing, by a molecular beam epitaxy process, a spatially periodic semiconductor layer structure in the form of a superlattice composed of an alternating arrangement of semiconductor layers of at least two different semiconductor compositions forming at least one heterojunction, one of the different semiconductor composition being SiGe, the improvement comprising:

• producing, by the molecular beam epitaxy process, in at least one of the SiGe semiconductor layers a doped layer which extends essentially parallel to the heterojunction and whose layer thickness is no greater than the thickness of the SiGe semiconductor layer in which it is produced, and producing at least one of the semiconductor layers forming a heterojunction with a subcritical layer thickness.