Advanced Energetic and Lateral Sensitive Charge Pumping Profiling Methods for MOSFET Device Characterization—Analytical Discussion and Case Studies

Since it is generally accepted that interface states play an important role in MOS device degradation, measurement tools, like charge pumping (CP) gain more and more influence in interface characterization and reliability issues. In this paper, we point out that an often neglected and hardly published constant base-level technique offers more flexibility and more accuracy than a classical constant amplitude technique which provides the well-known Gaussian-like CP curve. We present both energetic and lateral sensitive profiling techniques and point out several sources of errors that can occur when CP experiments are executed. Two different energetic profiling techniques are compared by means of a case study on negative bias temperature instability. In order to determine the exact location of degradation inside the transistor channel, the seldom published but well working constant field channel modulation technique is introduced as a special feature of the constant base-level technique. The tested devices are PMOS transistors with a 30-nm SiO₂ gate oxide and a gate length of 6 mum.