Oxide defects and reliability of high K/Ge and III?V based gate stacks

To date, gate stacks for high mobility semiconductors like Ge and InGaAs have been generally designed to minimise their interfacial trap density, and thus include an Al oxide layer diffusion barrier as a component. However, this is now known to lead to reduced reliability. The source of the problem is discussed and possible solutions based on an AlN or AlON layer component are suggested instead. First, we discuss traps in HfO₂-based Si gate stacks and their reliability.