In situ atomic layer nitridation on the top and down regions of the amorphous and crystalline high-K gate dielectrics

Amorphous and crystalline ZrO ₂ gate dielectrics treated with in situ atomic layer nitridation on the top and down regions (top and down nitridation, abbreviated as TN and DN) were investigated. In a comparison between the as-deposited amorphous DN and TN samples, the DN sample has a lower leakage current density (J _g ) of ∼7 × 10 ⁻⁴  A/cm ² with a similar capacitance equivalent thickness (CET) of ∼1.53 nm, attributed to the formation of SiO _x N _y in the interfacial layer (IL). The post-metallization annealing (PMA) leads to the transformation of ZrO ₂ from the amorphous to the crystalline tetragonal/cubic phase, resulting in an increment of the dielectric constant. The PMA-treated TN sample exhibits a lower CET of 1.22 nm along with a similar J _g of ∼1.4 × 10 ⁻⁵  A/cm ² as compared with the PMA-treated DN sample, which can be ascribed to the suppression of IL regrowth. The result reveals that the nitrogen engineering in the top and down regions has a significant impact on the electrical characteristics of amorphous and crystalline ZrO ₂ gate dielectrics, and the nitrogen incorporation at the top of crystalline ZrO ₂ is an effective approach to scale the CET and J _g , as well as to improve the reliability.