Comparison of electrical characteristics for SiONx and HfZrOx gate dielectrics of MOSFETs with decoupled plasma nitridation treatment

• The gate leakage with oxynitride dielectric around 1.5 nm thickness was sensed.
• The gate leakage with HfZrOx dielectric around 1.5 nm thickness was extracted.
• The ON currents for both devices were measured and compared.
• The difference of leakage mechanisms for both was illustrated.
• We probe the discrepancy for both devices in electrical characterization.

The gate leakage with oxynitride (SiONx) as a gate dielectric is lower than that with high-K (HfZrOx) around one order at VGS = ±0.8 V under the close physical gate thickness (∼1.5 nm) and device geometry. The subthreshold swing value in n-channel device grown with SiONx plus poly-Si gate is also superior to that for high-K gate dielectric with metal gate, but the phenomenon in p-channel device is changed due to the boron penetration from gate to channel surface. On the basis of the extracted data, the entire ON current with high-K dielectric is still better than that with oxynitride. The raise-up ratio is up to the maximum 51%. Although the possible existence of nano-crystallization, trap species or oxygen vacancy in high-K is increased to indirectly advance the higher leakage, the desired benefit to promote the drive current is still approached.

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