High-mobility two-dimensional electron gas structure for modulation-doped GaAs transistors

Utilizing two spacer regions of AlxGa1−xAs (x=0.41) and an intervening superlattice region of ten periods of GaAs/AlGaAs, 100 Å per period, an optimization of the electron mobility and concentration was obtained. An electron mobility of 131 000 cm2/V s was obtained at 77 K with an electron sheet concentration of 1.2×1012 cm−2.