Comparison of equivalent oxide thickness and electrical properties of atomic layer deposited hafnium zirconate dielectrics with thermal or decoupled plasma nitridation process

The NH ₃ thermal annealing and decoupled plasma nitridation (DPN) processes are compared for the equivalent oxide thickness (EOT) scaling of atomic-layer-deposited hafnium zirconate (HfZrO ₂) gate dielectric. Detailed physical, optical, and electrical characteristics of nitrided HfZrO ₂ (HfZrON) film are reported. It is found that DPN can yield a thinner SiO _x interfacial layer (IL) (about 0. 12 nm more in terms of EOT scaling) and a more densified HfZrO ₂ layer compared to those obtained using NH ₃ thermal annealing at a 16% nitrogen dose. NH ₃ thermal nitridation causes a large nitrogen distribution tail at the SiO _x IL/Si substrate interface and increases leakage current, which suppresses EOT scalability.