On the Physical Mechanism of NBTI in Silicon Oxynitride p-MOSFETs: Can Differences in Insulator Processing Conditions Resolve the Interface Trap Generation versus Hole Trapping Controversy?

Abstract

Negative bias temperature instability (NBTI) is studied in plasma (PNO) and thermal (TNO) Si-oxynitride devices having varying EOT. Threshold voltage shift (DeltaV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) and its field (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OX</sub> ), temperature (T) and time (t) dependencies obtained from no-delay on-the-fly linear drain current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DLIN</sub> ) measurements are carefully compared to that obtained from charge pumping (CP). It is shown that thin and thick PNO and thin TNO devices show very similar NBTI behavior, which can primarily be attributed to generation of interface traps (DeltaN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IT</sub> ). Thicker TNO devices show different NBTI behavior, and can be attributed to additional contribution from hole trapping (DeltaN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</sub> ) in pre-existing bulk traps. A physics based model is developed to explain the experimental results.