Defect configurations of high-k cations in germanium

Abstract

At germanium/high-k interfaces cations and oxygen interstitials can diffuse into the germanium substrate. Here we employ density functional theory calculations to investigate the interaction of a range of such cations (Al, Y, Zr, Nb, La, and Hf) with intrinsic defects and oxygen in germanium. It is predicted that high-k cations strongly bind with lattice vacancies, oxygen interstitials, and A-centers. The implications for microelectronic device performance are discussed.

Dopant-defect interactions in Ge: Density functional theory calculations

“…For example, the binding energy of an A-center next to a yttrium atom (refer to Fig. 1(c) and (d)) is calculated to be around 4 eV [40].…”

Strategies to suppress A-center formation in silicon and germanium from a mass action analysis viewpoint

“…The introduction of an isovalent dopant in Ge with a high binding energy with respect to V would readily form pairs with vacancies that will have increased thermal stability. In a recent DFT work [44] (using the same methodology as in [36,38,43]) it is calculated that the binding energies of the zirconium-V (ZrV) and hafnium-V (HfV) pairs in Ge are -1.89 eV and -1.85 eV respectively. Therefore, we propose that doping with Hf or Zr can prove an efficient strategy to trap vacancies in clusters thus constraining their participation in defect processes such as the formation of A-centers or the enhanced diffusion of n-type dopants.…”

Oxygen defect processes in silicon and silicon germanium

“…Controlling defects can be important during wafer fabrication and device processing in order to prevent device degradation. [7][8][9][10][11][12][13][14][15] O-related defects have been investigated systematically in Si and to a lesser degree in Ge or Si 1Àx Ge x for over five decades. This is because O, which is introduced in the lattice mainly due to the growth or processing stages, impacts the properties of Si and Si 1Àx Ge x .…”