Impact of plasma post-nitridation on HfO2/Al2O3/SiGe gate stacks toward EOT scaling

- Al2O3 interlayer with plasma post-nitridation can reduce Dit of HfO2/Al2O3/SiGe.
- Dit toward valance band is decreased by this method, compared with HfO2/SiGe MOS.
- There is an universal relationship between the Dit and ΔEOT by post-nitridation.
- 0.28-nm Al2O3 with 150-W microwave plasma achieves Dit ∼ 1011 cm−2 eV−1, ΔEOT ∼ 0.3 nm.
- With this method, we can achieve EOT scaling of HfO2/Al2O3/SiGe MOS with low Dit.