Oxidation Studies of Crystalline CVD Silicon Nitride

Abstract

15271. The diffusion model successfully predicted minimum A1 concentrations for protective A1203 scale formation during cyclic oxidation of Ni-Cr-AI(Zr) alloys containing more than 20% Cr.2. The success of the diffusion model in predicting N~ is strongly dependent on the ability to account for partial oxide spallation. The use of the oxide spalling model (16) provides this ability.3. It is not necessary to account for surface recession or the effect of the Cr concentration gradient on the diffusion of A1 when predicting minimum A1 concentrations for protective A1203 scale formation on Ni-Cr-AI(Zr) alloys.4. The decrease and subsequent recovery in the value of the solute concentration at the alloy surface is dependent on the amount of oxide which spalls each cycle and increases with an increasing number of thermal cycles. The increase in the amount of recovery with an increasing number of cycles is without a satisfactory explanation. ABSTRACTOxidation studies of CVD a-Si3N4 were performed in dry oxygen, oxygen-argon, and oxygen-nitrogen-argon gas mixtures of various oxygen and nitrogen partial pressures at a total pressure of I atm at 1100~176Parallel oxidation studies of single-crystal silicon were also conducted for direct comparison. It was observed that the oxidation of both Si3N4 and Si followed parabolic growth kinetics with activation energies of about 115 kcal/mol and about 30 kcal/mol, respectively. The formation of a single layer of SiO2 and evolution of N2 could not account for the much lower parabolic rate constants and much higher activation energy for Si3N4 than for Si during the oxidation. Detailed characterization of the oxidation scales using ellipsometry, step-by-step etching, SIMS, and XPS techniques indicated that a duplex oxidation scale consisting of SiO2 and SieN20 was formed when Si3N4 was oxidized. The intermediate Si2N20 scale was identified as a singlephase material, not a physical mixture of Si3N4 and SIO2. The low oxidation rate and high activation energy for SigN4 during the oxidation were attributed to the formation of Si2N20 and low oxygen diffusivity in this structurally dense phase. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.81.226.78 Downloaded on 2014-09-04 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.81.226.78 Downloaded on 2014-09-04 to IP ABSTRACTThe available thermodynamic and phase equilibria data for the binary systems Cd-Te, Cd-Se, and Cd-S have been analyzed using an associated solution model for the liquid phases and considering the CdTe, CdSe, and CdS phases as line compounds. The phase diagrams and the thermodynamic properties calculated from the model parameters agree well with the experimental data.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.81.226.78 Downloaded on 2014-09-04 to IP

Corrosion of Ceramic Materials

“…The evidence that supports a discrete oxynitride phase is the discontinuity in the etching rate of the oxide scale formed on silicon nitride (Du et al, 1989a) as well as the contrast observed in TEM and SEM images of scale cross-sections (Ogbuji and Smialek, 1991). An SEM image of the oxynitride/oxide formedon Si3N4 is shownin Figure8.…”

“…The oxidation of silicon nitride typically occurs with parabolic kinetics (Choi et al (1989), Du et al, 1989a;Schiroky et al (1986); Ogbuji and Opila, 1995), is dependent on oxygen partial pressure, and is independent of nitrogen partial pressure (Du et al, 1989a). These three observations show that the oxidation kinetics are controlled by oxygen transport across a growing scale.…”

Through a Window, Brightly: A Review of Selected Nanofabricated Thin-Film Platforms for Spectroscopy, Imaging, and Detection

“…20,64,66,[102][103][104][105][106] This history dependence can perhaps be appreciated most easily through a survey of the silicon oxynitride (SiO x N y ) literature, or through the variability of experimental outcomes when proper care is not taken. 66,107,108 A surface oxide coating readily forms in air (and can lead to an oxide gradient into the film), 102,108,109 and the susceptibility of Si 3 N 4 to evolve ammonia by hydrolysis in the presence of liquid-and vapor-phase water should also be considered. 102,103 In spite of this, SiN x shows very strong chemical resistance to a wide range of etchants and conditions, and indeed, etch resistance is the mechanism by which the film is made freestanding.…”

“…111 The surface can be generally conditioned using standard approaches such as exposure to a suitable oxidizing or reducing environment, or wet etching including hydrofluoric acid (and analogues) or piranha solution (and analogues). 20,47,64,102,106,108,[114][115][116][117][118][119][120][121][122][123] Specialized extensions of these methods can bring additional chemical flexibility. 20,64,104 Silane chemistry is a common route to surface chemical functionalization, but one that can be undermined by insufficient attention to either the SiN x process history or to the demands of the silane reaction itself.…”

Synthesis of Diagnostic Silicon Nanoparticles for Targeted Delivery of Thiourea to Epidermal Growth Factor Receptor-Expressing Cancer Cells

“…42 The third component at 100.91 eV is assigned to Si-Si within silicon core of NPs. [43][44] The C1s spectrum is fitted with three components and a Shirley background, see Fig. 2c.…”