Charge pumping revisited - the benefits of an optimized constant base level charge pumping technique for MOS-FET analysis

Since it is generally accepted that interface states play an important role in MOS device degradation (V. Huard et al., 2006), measurement tools like CP (charge pumping) gain more and more influence in interface characterization and reliability issues. In this paper we point out that the often neglected and hardly published constant base level technique offers more flexibility and more accuracy than the classical constant amplitude technique which provides the well known Gaussian-like CP curve (Bosch et al., 1991), (D. Bauza, 2003), (H.D. Okhonin, 1996). We present both energetic and spatial profiling techniques and point out several sources of errors that can occur when CP experiments are executed. In order to determine the exact location of degradation inside the transistor channel, the seldom published but well working constant field channel modulation technique (J.S. Brugler and P.G.A. Jespers, 1969) is introduced as a special feature of the constant base level technique.