Degradation of the gate oxide is often studied by stressing of metal-oxide-semiconductor (MOS) capacitors. Usually the MOS capacitor is stressed in accumulation to avoid the complications due to a voltage drop across the depletion layer if stressed in inversion. High field stressing studies for MOS capacitors with the silicon in inversion are presented in this article. Our observations show that in this mode, silicon properties (mainly minority 'carrier generation lifetime) play an important role.