The outstanding properties of SiO2, which include high resistivity, excellent dielectric strength, a large band gap, a high melting point, and a native, low defect density interface with Si, are in large part responsible for enabling the microelectronics revolution. The Si/SiO2 interface, which forms the heart of the modern metal–oxide–semiconductor field effect transistor, the building block of the integrated circuit, is arguably the worlds most economically and technologically important materials interface. This article summarizes recent progress and current scientific understanding of ultrathin (<4 nm) SiO2 and Si–O–N (silicon oxynitride) gate dielectrics on Si based devices. We will emphasize an understanding of the limits of these gate dielectrics, i.e., how their continuously shrinking thickness, dictated by integrated circuit device scaling, results in physical and electrical property changes that impose limits on their usefulness. We observe, in conclusion, that although Si microelectronic devices...

Ultrathin (<4 nm) SiO2 and Si-O-N gate dielectric layers for silicon microelectronics: Understanding the processing, structure, and physical and electrical limits

https://istina.msu.ru/media/publications/articles/573/a40/517515/X-Ray_Photoelectron_Spectroscopy_reference_data_for_C3N4.pdf

X-Ray photoelectron spectroscopy reference data for identification of the C3N4 phase in carbon–nitrogen films

A review of the preparation of carbon nitride films

Multiphase nanocomposite coatings (3–20 μm thick) consisting of nanocrystalline TiN, amorphous Si 3 N 4 , and amorphous and nanocrystalline TiSi 2 , nc-TiN/a-SiN x /a- and nc-TiSi 2 were deposited on steel substrates by means of plasma CVD. The load-independent Vickers microhardness from 80 to >105 GPa was measured by the load–depth sensing technique for applied loads between 30 and 200 mN and verified by measuring the size of the remaining plastic indentation using SEM. The results of a complex analysis provide a consistent picture of the nature of the grain boundaries which determines the hardness in the whole range of silicon content between approximately 3 and 22 at.%. At a high discharge current density of ≥2.5 mA/cm 2 the a-Si 3 N 4 forms the grain boundaries and the nanocomposites are superhard (40–50 GPa) as we reported earlier. At a lower current density of ≤1 mA/cm 2 a mixture of TiSi 2 and Si 3 N 4 is formed. With increasing Si-content the amount of a-TiSi 2 in the grain boundaries of the TiN nanocrystals increases, and above 10 at.% of Si approximately 3 nm small TiSi 2 nanocrystals precipitate. The hardness depends critically and in a complex way on the Si 3 N 4 content and the TiSi 2 /Si 3 N 4 ratio. The ultrahardness 1 of ≥80 GPa is achieved when the surface of the TiN nanocrystals is covered with approximately one monolayer of Si 3 N 4 . Under these conditions the ultrahardness of 80–100 GPa depends on the amount of a- and nc-TiSi 2 .

Composition, nanostructure and origin of the ultrahardness in nc-TiN/a-Si3N4/a- and nc-TiSi2 nanocomposites with HV= 80 to ≥ 105 GPa

The surface as molecular reagent: organic chemistry at the semiconductor interface

Photoemission study of ammonia dissociation on Si(100) below 700 K.

Use of multilayer techniques for XPS identification of various nitrogen environments in the Si/NH3 system

With use of x-ray photoelectron spectroscopy (XPS), the adsorption of ${\mathrm{NH}}_{3}$, both on c-Si(100) and during silicon nitride film growth, is comparatively examined over a wide range of substrate temperature ${T}_{S}$ between room temperature and 800 \ifmmode^\circ\else\textdegree\fi{}C, gas pressure P(${\mathrm{NH}}_{3}$), and exposure E. For sake of comparison with the surface parameters, dynamical exposure ${E}_{D}$ or exposure times ${t}_{D}$ are defined for the growth process. Both in surface adsorption and during film growth strongly correlated behaviors can be observed. They concern the following: (i) the general ${T}_{S}$-dependent evolution of the chemisorbed species, i.e., ${\mathrm{NH}}_{\mathrm{x}}$, H, and finally N, and (ii) the particular exposure and ${T}_{S}$ behaviors of the latter nitridation regime, occurring in the 350--800 \ifmmode^\circ\else\textdegree\fi{}C range.At high ${T}_{S}$ (600--800 \ifmmode^\circ\else\textdegree\fi{}C) and low ${\mathrm{NH}}_{3}$ pressure, growth of ${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ islands on the c-Si(100) surface is related to heterogeneous ${\mathrm{SiN}}_{\mathrm{x}}$-film formation presenting strong phase separation (Si and ${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ cluster mixture). Very low nitrogen uptake, governed by N thermal desorption increasing with ${T}_{S}$, is found in this domain. For higher ${\mathrm{NH}}_{3}$ pressures or exposures (${E}_{D}$ or Eg200 L, where L denotes langmuirs; 1 L${=10}^{\mathrm{\ensuremath{-}}6}$ Torr s) complete nitridation in thick ${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ films when Si is deposited or in a thin homogeneous ${\mathrm{Si}}_{3}$${\mathrm{N}}_{4}$ overlayer on the c-Si surface, is achieved. At lower ${T}_{S}$ (350--600 \ifmmode^\circ\else\textdegree\fi{}C) the nitrogen is chemisorbed at the surface in a more homogeneous way, the deficient bulk diffusion limiting interaction with the top layer and leading to a more rapid saturation of the nitrogen uptake with exposure. In this regime intermediate silicon subnitride environments Si-${\mathrm{N}}_{3}$Si are essentially found, whose counterpart for film deposition is nitride formation with a microstructure nearer to the random bonding model. Despite a ${T}_{S}$ shift, due to the room-temperature dissociative chemisorption of ${\mathrm{O}}_{2}$ on Si (while for atomic nitrogen it starts only above 350 \ifmmode^\circ\else\textdegree\fi{}C), we note a qualitative similarity between the main features involved in the initial, fast silicon nitridation stage and those occurring during oxidation.

L. Kubler

Papers

Photoemission study of ammonia dissociation on Si(100) below 700 K.

Use of multilayer techniques for XPS identification of various nitrogen environments in the Si/NH3 system

General comparison of the surface processes involved in nitridation of Si(100)- 2×1 by NH 3 and in SiN x film deposition: a photoemission study

Search for carbon nitride CNx compounds with a high nitrogen content by electron cyclotron resonance plasma deposition

Si-H bond production by NH3 adsorption on Si(111): An UPS study