The HKMG construction has been proposed in order to resolve various problem that arise in conjunction with developments involving reductions in the power supply voltage, increases in the speed, and increases in the degree of integration of transistors.
With transistors having an HKMG construction, it is known that the threshold shifts in accordance with the state of diffusion of oxygen in the high dielectric-constant (high-k) gate insulating film being employed (see patent literature articles 1 or 2, for example).