Double nitridation of crystalline ZrO 2 /Al 2 O 3 buffer gate stack with high capacitance, low leakage and improved thermal stability

Jhih Jie Huang, Yi Jen Tsai, Meng Chen Tsai, Min Hung Lee, Miin Jang Chen

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5 Citations (Scopus)


The gate dielectric stack composed of crystalline ZrO 2 and Al 2 O 3 buffer layer treated with double nitridation was developed to reduce the capacitance equivalent thickness (CET), leakage current density (J g ), interfacial state density (D it ), and enhance thermal stability as well. A high dielectric constant of the gate stack was provided by the crystalline ZrO 2 with tetragonal/cubic phase. The J g and D it were suppressed by the insertion of the Al 2 O 3 buffer layer treated with remote NH 3 plasma nitridation because of the deactivation of the oxygen vacancies and the well passivation of the Si dangling bonds. A further nitridation using remote N 2 plasma on ZrO 2 was carried out to reduce the CET and J g by the enhancement of the dielectric constant and the deactivation of the grain boundaries and oxygen vacancies. Accordingly, a low CET of 1.09 nm, J g of 3.43 × 10 -5 A/cm 2 , and D it of 3.35 × 10 11 cm -2 eV -1 were achieved in the crystalline ZrO 2 /Al 2 O 3 buffer gate stack treated with the double nitridation. The hysteresis was also minimized significantly by the post-deposition annealing at 800 °C, which is attributed to the enhanced thermal stability. The results indicate that the crystalline high-K dielectrics/buffer layer with double nitridation treatments is a promising gate stack structure beneficial to the sub-nanometer CET scaling in the future.

Original languageEnglish
Pages (from-to)221-227
Number of pages7
JournalApplied Surface Science
Publication statusPublished - 2015 Mar 1



  • Atomic layer deposition
  • Buffer layer
  • High-K gate dielectrics
  • Nitridation
  • Zirconium oxide

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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