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 ap plied to the synthesis of SiGe relaxed buffer layers with Ge end concentrat ions between 35% and pure Ge. A growth rate of several nanometres per secon d for relaxed buffer lavers is well above that obtainable by any other grow th technique. The structural quality of SiGe buffers graded to pure Ge is c ompared with that of a Ge buffer of constant composition. The structural qu ality 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 p roperties have been characterized by magneto transport measurements. (C) 20 00 Elsevier Science S.A. All rights reserved.