Nondestructive analysis of Si3N4/SiO2/Si structures using spectroscopic ellipsometry

Theeten, J. B.; Aspnes, D. E.; Simondet, F.; Erman, M.; Mürau, P. C.

doi:10.1063/1.328633

Cited by 30 publications

(13 citation statements)

References 19 publications

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“…The SiO2 thickness observed here is then compared to estimates of a 15-20/k equivalent thickness of "SiO~" in other nitride samples (11). First, it must be remem-) unless CC License in place (see abstract).…”

Section: Methodsmentioning

confidence: 95%

See 1 more Smart Citation

Compositional Depth Profile of a Native Oxide LPCVD MNOS Structure Using X‐Ray Photoelectron Spectroscopy and Chemical Etching

Wurzbach

Grunthaner

1983

J. Electrochem. Soc.

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A compositional profile of a native oxide LPCVD MNOS structure has been obtained byx-ray photoelectron spectroscopy used in conjunction with a stopped-flow chemical etching procedure. A depth resolution of 5-10A was achieved. Stoichiometric Si3N4 was found in the bulk with about 0.4 atomic percent (a/o) oxygen impurity. In contrast to profiles completed by other techniques, SiO2 was found intact at the interface; complete conversion of oxide to oxynitride during LPCVD did not occur. The oxide/nitride interface is best described as sharp; the oxygen concentration drops by 80% in less than 8A. There is also a diffuse oxynitride gradient extending into the film, but the oxygen concentration in this region is quite low. Evidence was also found for an 8~ layer containing excess bonds to silicon between the oxide and nitride layers. Possible charge trap structures that might limit device performance are discussed along with processing suggestions aimed at minimizing the formation of traps.Studies of the composition and interfaces of silicon nitride on oxidized silicon have been driven by the wide application of these structures in electrically alterable, nonvolatile MNOS memory devices (1). Many of the electrical properties of these devices are related to the structure and composition of the nitrideoxide and oxide/silicon interfaces. Charge storage in MNOS structures involves modified Fowler-Nordheim tunneling across the thin oxide layer to traps at or beyond the nitride/oxide interface (2). Shifts in the logical voltage window have been related to states at the oxide/substrate interface (1). Endurance and retention problems (1) manifest themselves after repeated write/erase cycling moves charge across MNOS interfaces. It is, therefore, desirable to achieve an accurate understanding of the structure and composition of MNOS systems in the bulk region and particularly at the interfaces.Numerous techniques have been applied to the characterization of silicon nitride and MNOS interfaces including: Auger electron spectroscopy (AES) (3-9), energy-loss spectroscopy (ELS) (10), spectroscopic ellipsometry (SE) (8, 1!), Rutherford backscattering (RBS) (5c, 8, 12, 14), nuclear-reaction analysis (5c, 1"|, 15), secondary ion mass spectroscopy (SIMS) (9b), multiple internal reflection (MIR) (5c, 15, 16), and x-ray photoelectron spectroscopy (XPS) (17).AES work has been done in conjunction with argon ion sputtering to obtain profiles of composition vs.depth. Early work (3) suggested an apparent width of 20-30A FWHM, or 50A 10/10%, for the interface between bulk silicon nitride and the silicon substrate of memory-type MNOS structures. These estimates were not corrected for the broadening effects of differential Key words: silicon nitride etching, charge trap structures, traps. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.255.6.125 Downloaded on 2015-06-13 to IP

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Section: Methodsmentioning

confidence: 95%

“…For example, SE data have identified an optically absorbing region between the oxide and nitride layers (11). For example, SE data have identified an optically absorbing region between the oxide and nitride layers (11).…”

mentioning

confidence: 99%

Compositional Depth Profile of a Native Oxide LPCVD MNOS Structure Using X‐Ray Photoelectron Spectroscopy and Chemical Etching

Wurzbach

Grunthaner

1983

J. Electrochem. Soc.

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“…They are taken entirely from the work of Philipp [21]. In addition, Theeten et al [23] in a study of Si3N 4 in the region from 1.5 to 5.8 eV using spectroscopic ellipsometry found good agreement with the values of Philipp [21] (and it is in this energy range that the largest differences occur between the results of Philipp [21] and Bauer [22]). In addition, Theeten et al [23] in a study of Si3N 4 in the region from 1.5 to 5.8 eV using spectroscopic ellipsometry found good agreement with the values of Philipp [21] (and it is in this energy range that the largest differences occur between the results of Philipp [21] and Bauer [22]).…”

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confidence: 90%

Silicon Nitride (Si3N4) (Noncrystalline)

Philipp

1997

Handbook of Optical Constants of Solids

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“…In the first one we have optimized the thickness of a pure titanium layer on a silicon substrate. A substantial improvement is obtained once the titanium layer is allowed to contain voids reflecting the titanium microstructure [6,9]; the residue becomes 8.5 × 10 -3, which for the case of this kind of analysis becomes an acceptable fit [1][2][3][4][5]. These voids are incorporated by means of the Bruggeman effective medium theory [29][30][31].…”

Section: Lhe As-deposited Layermentioning

confidence: 99%

“…buried oxide or nitride layers [1][2][3][4][5]. Metallic systems have the disadvantage that the dielectric functions required are not uniquely known [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%