A comparative study of gate stack material properties and reliability characterization in MOS transistors with optimal ALD Zirconia addition for hafina gate dielectric

In this work, we investigate the influence of incorporation Zirconia (ZrO
₂
) in gate dielectric HfO
₂
on electrical properties and the reliability of nMOSFET for the 28nm technology node. Detailed film physical, chemical and optical properties of Hf
_1-x
Zr
_x
O
₂
as a function of Zr content were studied using HRTEM, AR-XPS, spectroscopic ellipsometer. Compared to HfO
₂
, Hf
_1-x
Zr
_x
O
₂
provides lower C-V hysteresis, V
_t
shift (ΔV
_t
) and higher Time to Failure (TTF) lifetimes are achieved with Zr incorporation in an ALD Hf
_1-x
Zr
_x
O
₂
/SiO2 gate stack. The improved reliability of the Hf
_1-x
Zr
_x
O
₂
gate dielectric is attributed to the reduced charge trapping in the Hf
_1-x
Zr
_x
O
₂
gate dielectric caused by the Zr incorporation.