Characterization of leakage behaviors of high-k gate stacks by electron-beam-induced current

Microscopical investigation of leakage behaviors of Hf-based high-k gate stacks was achieved by means of electron-beam-induced current (EBIC) method. Carrier separated EBIC measurement has found that in non-stressed samples, hole conduction in pMOS is significantly enhanced by trap-assisted tunneling, while electron conduction in nMOS is independent of traps. The transport mechanisms of electron and holes in non-stressed high-k MOS capacitors were clarified. After stressing, positive charged traps are induced in nMOS and enhance electron conduction.