We have successfully grown Si0.3Ge0.7/strained Ge channel/Si0.3Ge0.7 heterostructures with ultrahigh hole mobility on Si (10 0) substrates by solid source molecular beam epitaxy. Suppression of parallel conduction, which commonly exists in SiGe heterostructures was achieved by employing n-type doping in thick SiGe buffer layers, which resulted in the drastic increase of room-temperature (RT) Hall hole mobility up to 2100 cm(2)/V S. Using this technique, p-type metaloxide-semiconductor field-effect transistors without parallel conduction were successfully fabricated and the peak effective hole mobility of 2700 cm(2)/V s at RT was obtained, which was much higher than that of bulk Ge drift mobility. (C) 2002 Elsevier Science B.V. All rights reserved.