Virtual substrates for the n- and p-type Si-MODFET grown at very high rates

Low-energy plasma-enhanced chemical vapour deposition (LEPECVD) has been applied to the synthesis of SiGe relaxed buffer layers with Ge end concentrations between 35% and pure Ge. A growth rate of several nanometres per second for relaxed buffer layers is well above that obtainable by any other growth technique. The structural quality of SiGe buffers graded to pure Ge is compared with that of a Ge buffer of constant composition. The structural quality of the pure Ge buffer is remarkably good compared with the much more complicated graded buffer. Complete n-type Si-modulation doped field effect transistor structures have been synthesized by LEPECVD, and the electric properties have been characterized by magneto transport measurements.