Super-doped structure.

Super-doped structure (SDS) is reviewed. This is a very short period AlAs/GaAs superlattice in which the GaAs mid-layers are selectively doped with Si donor impurities, and is able to suppress the DX-center formation in n-type Al-Ga-As system. A new SDS concept and structural optimizations for replacing AlxGa1-xAs alloys and realizing high electron concentration are discussed. Superior electrical properties of SDS are shown in comparison with n-type AlxGa1-xAs (x>0.2) alloys. The applications of SDS to high speed devices and the prospects of other materials using this concept are presented. [J. Cryst. Soc. Jpn. 28, 142 (1986) ] .