Record-Low EOT(3.6Å) & J_leak(7×10^-8A/cm²@0.8V) HZO by Dielectric-Selective Microwave Annealing

In this work, we present HZO film near the morphotropic phase boundary (MPB) with an EOT of 3.6 Å and a low leakage current density (J<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">leak</inf> @ 0.8 V) of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{J}_{\text{leak}}(7.0\times 10^{-8}\mathrm{A}/\text{cm}^{2}{@}$</tex> using a microwave annealing (MWA) system. The MWA supplies the energy required for HZO crystallization in both thermal and microwave forms, offering three key benefits: (i) It drastically reduces thermal budget (TB), suppresses interfacial dead layer formation, and enhances endurance (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{K}\sim 62$</tex> at 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cycles). (ii) It only affects the HZO film and not the TiN electrodes, making the dipoles inside HZO vibrate. This enables selective and volumetric annealing in high-aspect-ratio DRAM cell capacitors. (iii) It lowers the activation barrier for HZO crystallization compared to typical rapid thermal annealing (RTA). We experimentally verified this by quantifying activation energy (E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf>) using electrical measurements under various TBs, finding that the E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> was 0.67 eV/f.u. for MWA, and 0.85 eV/f.u. for RTA.