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

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 E_high-k ε_high-k = Q + E_sio2ε_sio2.