Structural advantage for the EOT scaling and improved electron channel mobility by incorporating dysprosium oxide (Dy/sub 2/O/sub 3/) into HfO/sub 2/ n-MOSFETs

A structural approach of fabricating laminated Dy
₂
O
₃
-incorporated HfO
₂
multimetal oxide dielectric has been developed for high-performance CMOS applications. Top Dy
₂
O
₃
laminated HfO
₂
bilayer structure shows the thinnest equivalent oxide thickness (EOT) with a reduced leakage current compared to HfO
₂
. This structure shows a great advantage for the EOT scaling CMOS technology. Excellent electrical performances of the Dy
₂
O
₃
/HfO
₂
multimetal stack oxide n-MOSFET such as lower V
_T
, higher drive current, and an improved channel electron mobility are reported. Dy
₂
O
₃
/HfO
₂
sample also shows a better immunity for V
_t
instability and less severe charge trapping characteristics. Two different rationed Dy
₂
O
₃
/HfO
₂
and HfO
₂
n-MOSFET were measured by charge-pumping technique to obtain the interface state density (D
_it
), which indicates a reasonable and similar interface quality. Electron channel mobility is analyzed by decomposing into three regimes according to the effective field. Reduced phonon scattering is found to be the plausible mechanism for higher channel mobility