through several channels higher transconductances for transistors are obtained with this resulting in the promise of shorter switching times especially for integrated circuits in addition other characteristics that are critical for the high frequency technology such as transit frequency and maximum operating frequency can also be increased application_number US 6655998 A description the exemplary embodiment according to fig1 shows a layer sequence for a hfet the substrate 1 used here is a monocrystalline silicon substrate with orientation 100 generally used in semiconductor production which has a specific resistance of for example 10 3 u03c9cm as a result interfering parasitic capacities and leakage currents in the substrate material are prevented with the aid of molecular beam epitaxy mbe for example the layer sequence is permitted to grow over the complete surface of the si substrate 1 in order to adjust the electrical and or mechanical characteristics of the conducting channels a buffer layer 2 e g consisting of undoped si 0 7 ge 0 3 initially follows the substrate 1 the complete buffer layer 2 has a thickness of approximately 1 u03bcm the effect of the buffer layer 2 is that crystal defects are primarily localized at the boundary layer formed between the substrate 1 and the buffer layer 2 and that an exact mechanical voltage distribution for the succeeding semiconductor.