Most of the electronic integrated circuits used today are Complementary MOS (CMOS) circuits, which consist mainly of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs). In the last forty years there has been a tremendous reduction of the MOSFET dimensions. This reduction will continue, enabling even faster and more complex integrated circuits. But, there are a number of hurdles on the road. One of these hurdles is the thickness reduction of an essential electrically isolating layer inside the MOSFET, the so-called gate dielectric. This gate dielectric is becoming so thin, it starts to leak electrical current under operating conditions. This increases the power consumption and can lead to a non-functional transistor. Reliability is also of concern, because the gate dielectric deteriorates under device operation, leading to even larger leakage currents.