Direct contact of high-k/Si gate stack for EOT below 0.7 nm using LaCe-silicate Layer with Vfb controllability

A direct high-k/Si gate stack has been proposed for gate oxide scaling. With LaCe-silicate, an EOT of 0.64 nm with an average dielectric constant (k
av
) of 17.4 has been obtained and an extremely low gate leakage current (J
g
) of 0.65 A/cm
²
. The flatband voltage (V
fb
) can be controlled by the compositional ratio of La in the LaCe-silicate layer. Furthermore, incorporation of Ge atom into the silicate layer can effectively shift the V
fb
to positive direction.