Ultra high hole mobility in Ge films grown directly on Si (1 0 0) through interface modulation

Abstract

We have demonstrated an effective method to achieve ultra high mobility in the Ge films grown directly on Si (100) using molecular beam epitaxy (MBE). The Hall effect measurements revealed that the unintentionally doped Ge films have a hole mobility up to 1252 cm2/V·s at room temperature and 3855 cm2/V·s at 80 K. A proper combination of low temperature epitaxy and high temperature post annealing provides the opportunity on defect reduction and interface modulation. The periodic 90° interfacial misfit (IMF) array formed at the Ge/Si interface is believed to contribute to a preferential strain relieve at the interface and the ultra high mobility.