Investigation of an anomalous hump in gate current after negative-bias temperature-instability in HfO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors

Abstract

This Letter investigates a hump in gate current after negative-bias temperature-instability (NBTI) in HfO2/metal gate p-channel metal-oxide-semiconductor field-effect transistors. Measuring gate current at initial through body floating and source/drain floating shows that hole current flows from source/drain. The fitting of gate current (I-g)-gate voltage (V-g) characteristic curves demonstrates that the Frenkel-Poole mechanism dominates the conduction. Next, by fitting the gate current after NBTI, in the order of Frenkel-Poole then tunneling, the Frenkel-Poole mechanism can be confirmed. These phenomena can be attributed to hole trapping in high-k bulk and the electric field formula Ehigh-k epsilon(high-k) = Q+E-sio2 epsilon(sio2). (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773479]