u03b4l from a selected reference point associated with each ge pulse a change in the so called doping phase angle u03c6 2 u03c0 u00b7 u03b4l l makes it possible for example to dope with sb either only the si semiconductor layers or only the si 0 55 ge 0 45 semiconductor layers surprisingly it has been noted that sb doping in only the si 0 55 ge 0 45 semiconductor layers results in a significant increase in electron mobility in the created superlattice fig2 shows the dependency of the hall mobility u03bc h of the electrons on operating temperature t for various semiconductor materials curve 1 relates to monocrystalline si material with a homogeneous sb doping of 4 u00d7 10 18 cm 3 curve 2 relates to si 0 75 ge 0 25 semiconductor material with a homogeneous sb doping of 4 u00d7 10 18 cm 3 curve 3 relates to a superlattice of alternating si and si 0 55 ge 0 45 layers each layer having a spatial period duration corresponding to the period l of about 10 nm and composed of 10 periods or layer pairs in this superlattice only the si 0 55 ge 0 45 semiconductor layers are doped with sb with an area concentration n s 4 10 12 cm 2 fig2 shows that the electron mobility according to curve 3 at room temperature 300 u00b0 k is approximately four times as high as.