Phase and surface roughness evolution for as-deposited LPCVD silicon films

Cobianu, C.; Plugaru, R.; Nastase, N.; Nastase, Samuel A.; Flueraru, Costel; Modreanu, M.; Adamczevska, J.; Paszkowicz, W.; Auleytner, J.; Cosmin, P.

doi:10.1051/jp4:19998135

Cited by 8 publications

(8 citation statements)

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“…As can be seen from Figure 2 and Table II, there is a minimum in the asperity density, height, and roughness at 550°C and a drastic increase at 560°C. This is in agreement with Cobianu et al 25 who found a minimum in roughness at a deposition temperature of 550°C. They showed, using an x-ray diffraction technique, the presence of a polycrystalline stage in as-deposited films that were deposited at a temperature below or above 550°C, but not in films that were deposited at 550°C.…”

Section: Amorphous Silicon Surface Morphology As a Function Of Deposisupporting

confidence: 91%

Silicon nano-asperities: Morphological evolution and electrical properties of double-polysilicon interlayers

Edrei

Shauly

Roizin

et al. 2004

Journal of Elec Materi

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Polysilicon/silicon-dioxide/polysilicon structures (double polysilicon) are grown by deposition of amorphous silicon followed by thermal oxidation and a final polysilicon deposition process. Correlation between the appearance of silicon nano-structures and surface morphology formed during the amorphous silicon deposition stage and the electrical characteristics of the double poly capacitor have been investigated. It is shown that the process parameters have a pronounced effect on the morphological properties of the film surface. Nanometric size asperities form during the amorphous silicon deposition stage. The density and height distribution of these asperities were found to depend on deposition temperature. Thermal oxidation of the amorphous layer resulted in the growth of a top oxide layer and crystallization of the bottom silicon film. This process results in an overall increase of the surface roughness and a pronounced decrease in the height of the nano-asperities. By HF-etching the oxidized film, the surface of the polycrystalline silicon is exposed. Following this etching process, the surface roughness increases, whereas the density and height of the nano-asperities decrease. A correlation between the height of asperities on the bottom amorphous silicon film (as well as roughness of this film) and the breakdown voltage of the double poly was found.

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Section: Amorphous Silicon Surface Morphology As a Function Of Deposisupporting

confidence: 91%

Silicon nano-asperities: Morphological evolution and electrical properties of double-polysilicon interlayers

Edrei

Shauly

Roizin

et al. 2004

Journal of Elec Materi

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“…In our previous papers [6], [7], [8], [9], we have presented the kinetic results and the associated structural and morphological properties for the as-deposited LPCVD films prepared in a large range of deposition conditions (deposition pressure of 20-100 Pa and the deposition temperature ranging from 500-615" C). Now, we shall study the effect of the low temperature Nz annealing (600°C) on the physical properties of the LPCVD Si films.…”

Section: Results and Disscusionsmentioning

confidence: 99%

“…These methods will show the structural and morphological differences appeared in the annealed LPCVD Si film with respect to the asdeposited state o f . the same film [6].The crystallite size was determined using the single line analysis method from linewidth (full width at half maximum) by applying the DebyeScherrer formulae D = 0.9 A/(B cose) where h = 0.0710 nm (MO K, radiation), 8 is the Bragg diffraction angle and B is the linewidth at half maximum.…”

Section: Methodsmentioning

confidence: 99%

“…As mentioned in a previous paper [6], the LPCVD silicon films were prepared in ASM, standard, hot wall, resistance heated quartz reactor. The films were deposited on Si/SiO, substrates.…”

Section: Methodsmentioning

confidence: 99%

“…For the integrated circuits on glass substrate, like active matrix of liquid crystal display (AMLCD), the roughness and grain size of polysilicon should be carefully controlled at low temperature processing below 620°C Recently, we have extended the CVD conditions for the preparation of the LPCVD Si film to lower pressure (20 Pa) and deposition temperature (500°C) [6], [7]. The XRD investigations of these films have revealed for the first time a polycrystalline structure even for layers prepared at such low temperature [6]. Further structural investigations by W spectrometry [8] and spectroellipsometry (SE) [9] have confirmed the initial results obtained by XRD.…”

Section: Introductionmentioning

confidence: 99%

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Microphysical investigation of low temperature annealed LPCVD polysilicon thin films

Cobianu

Modreanu²,

Gärtner³

et al.

2001 International Semiconductor Conference. CAS 2001 Proceedings (Cat. No.01TH8547)

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In this paper we present the morphological and structural properties of the low pressure chemically vapor deposited (LPCVD) silicon films after annealing at 600°C for 26 hours in nitrogen, in comparison with the properties of asdeposited layers. For the films found in the polycrystalline state after deposition (i.e. those prepared at temperatures below and above 550"C), XRD spectra have indicated a supplementary (1 1 1) diffraction peak after annealing. In addition, from XRD data, we obtained a dependence of grain size of annealed Si layers on initial CVD conditions. The spectroellipsometry (SE) and Ultra-Violet (UV) spectroscopy have indicated an important increase of the crystalline/amorphous silicon ratio for all annealed films. The signature of initial CVD conditions in optical properties investigated by S E and UV was found only for as-deposited Si films.From AFM measurements we have found that the surface roughness has increased by annealing, with a higher value for the annealed films, which were in the poly-crystalline state, immediately after deposition. In connection to our earlier results we bring here further support (by S E and UV data) for the crystalline state detected in as-deposited LPCVD films prepared at temperatures as low as 500°C. The value of the amorphous fraction present in the asdeposited film can explain the structural changes of the LPCVD Si films after annealing, as a function of initial CVD conditions.

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