Kink effect for 28 nm n-channel field-effect transistors after decoupled plasma nitridation treatment with annealing temperatures

The kink effect of drain leakage based on gated diode measurement metrology for the tested nMOSFETs with 28 nm HK/MG, gate-last and PDA or DPN nitridation processes was observed at V_G around -0.6 V when the gate voltage was swept from -Vcc to 0.2 volt as V_D = 0.1 V. Nevertheless, this interesting phenomenon was not evident as the gate voltage was reversely swept from 0.2 volt to -Vcc. The chief mechanism in speculation can be illustrated by the electrons coming from drain inducing capture-and-emission behaviour by the channel interface traps near the drain junction. While V_Gchanges from -Vcc towards +0.2 V, interface states near valence band become lower than Fermi-level of silicon substrate. Electrons flow from drain to fill these interface states so that drive current (I_D) increases. On the contrary, as V_Gchanges from +0.2 V to -Vcc, the trapped electrons are recombined with holes from substrate so that I_D is not affected. This kink effect for all of tested devices is not very distinct far and near. When the Poole-Frenkel (P-F) tunnelling electrons coming from gate to drain are evident in leakage, especially at the long-channel device, this effect will be probably counteracted, exhibited at the electrical characteristics of PDA group.