Observation of leakage sites in high-k gate dielectrics in MOSFET devices by electron-beam-induced current technique

We have succeeded in imaging the leakage sites of hafnium silicate gate dielectrics of metal-oxide-semiconductor field-effect transistors (MOSFETs) by using electron-beam-induced current (EBIC) method. Leakage sites of p-channel MOSFETs were identified as bright spots under appropriate reverse bias condition when the electron beam energy is high enough to generate carriers in the silicon substrate. Most of the leakage sites were observed in the peripheries of shallow trench isolation. These results suggest that some process induced defects are the cause of leakage in these MOSFETs. Our observation demonstrates the advantage of EBIC characterization for failure analysis of high-k MOSFETs.