Combined electrical and electron spin resonance analysis revealed dramatic differences in the interface defect properties of the (100)Ge/GeOxNy/HfO2 and (100)Ge/GeO2 interfaces from the seemingly similar interfaces of (100)Si with the HfO2 and SiO2. No dangling bond centers associated with Ge crystal surface atoms were detected. Only paramagnetic defects in the near-interfacial Ge oxide or Ge (oxy)nitride layers were observed. In contrast to the amphoteric traps related to the dangling bonds (Pb-type centers) commonly observed at the Si/insulator interfaces, the major component of the Ge/insulator interface trap spectrum comes from slow acceptor states which showed no correlation with paramagnetic centers and were resistant to passivation by H.

Interface Traps and Dangling-Bond Defects in (100)Ge/HfO2. V.V.Afanasev, Y.G.Fedorenko, A.Stesmans: Applied Physics Letters, 2005, 87[3], 032107 (3pp)