Scattering mechanisms in high-mobility strained Ge channels

We report on the low-temperature mobility in remotely doped p-type strained Ge layers on relaxed Si0.3Ge0.7 virtual substrates, grown by low-energy plasma-enhanced chemical vapor deposition. A maximum mobility of 120000 cm(2) V-1 s(-1) has been reached at 2 K, at a carrier sheet density of 8.5x10(11) cm(-2). Analysis of the mobility and Dingle ratio pi/pi(g) as a function of sheet density suggests that remote impurity scattering is the limiting factor at low sheet densities, but that interface impurities become more important as the sheet density increases. (C) 2004 American Institute of Physics.