Ultrathin zirconium silicate film with good thermal stability for alternative gate dielectric application

Abstract

Zirconium silicate (ZrSixOy) films have been sputtered by comagnetron-reactive sputtering. The composition of ZrSixOy has been controlled by adjusting the sputtering powers of Si and Zr targets to achieve various effective dielectric constants. The sputtered silicate layers showed low equivalent oxide thickness of 14.5 Å with a low leakage of 3.3×10−3 A/cm2 at −1.5 V relative to flat band voltage. The silicate films also exhibited good high-temperature stability and smooth interfacial properties on silicon substrate.

Production of a hafnium silicate dielectric layer for use as a gate oxide by solid-state reaction

“…This shift will reduce the Si 2p BE, consistent with our observations. This shift provides evidence that the hafnium silicate/Si interface will be stable against interfacial SiO 2 formation (as predicted by Hubbard and Schlom [3] [4,5,6,7,9,10,12]. However, to our knowledge, there have been no previous observations of charge transfer during silicate formation to corroborate those structural findings.…”

“…These elements are among the most chemically similar found in nature, so the findings of one are often applicable to the other. [4,5,6,7,9,10,12]. It appears that a relatively small amount of Hf or Zr can significantly increase the dielectric constant [7,8].…”

Studies on Al2O3/ZrO2/Al2O3 high K gate dielectrics applied in a fully depleted SOI MOSFET

“…This requires new characterization techniques to assess material quality, a barrier to common SOI applications [12]. High frequency C-V characterization techniques are well-established means and have been applied for characterizing bulk Si MOS fabrication processes and MOS devices [13,14]. However, it is far more difficult for the case of a SOI MOS capacitor, the main part of a SOI MOSFET, due to the presence of two additional semiconductor-insulator interfaces.…”

Thermal stability and diffusion in gadolinium silicate gate dielectric films

“…Most of the effort has focused on insulators that are ''thermodynamically stable'' on Si substrates; i.e., when heated in contact with silicon will not directly react to form silicide, metal, or silicon oxide. 1 O 3 , and silicates such as ZrSiO 4 and HfSiO 4 . [2][3][4] It is generally assumed that other lanthanide oxides, such as Gd 2 O 3 , [5][6][7] or their silicates, 8 are also thermodynamically stable.…”

“…1 O 3 , and silicates such as ZrSiO 4 and HfSiO 4 . [2][3][4] It is generally assumed that other lanthanide oxides, such as Gd 2 O 3 , [5][6][7] or their silicates, 8 are also thermodynamically stable. However, even a thermodynamically stable film can react if excess oxygen in the film or from the ambient, or Si from the substrate, diffuse through the film and react with each other.…”