Point defects at interfacial layers in stacks of (100)Ge with nm-thin HfO2 and GeOx(Ny) insulators probed by electron spin resonance

Electron spin resonance studies of (1 0 0)Ge/GeOxNy/HfO2 and (1 0 0)Ge/GeO2 structures fail to reveal interfacial Ge dangling bond type defects. Only paramagnetic defects residing in near-interfacial Ge oxide or Ge(oxy)nitride layers could be observed, which in the former structures appear resistant to passivation treatment in H2 at 400 °C and show no correlation with the major portion of electrically active traps. The results indicate a fundamental difference between the seemingly similar group-IV elemental semiconductor/insulator interfaces for (1 0 0)Si and (1 0 0)Ge.