Improved size dispersion of silicon nanocrystals grown in a batch LPCVD reactor

2004 ◽  
Vol 830 ◽  
Author(s):  
Y. M. Wan ◽  
K. van der Jeugd ◽  
T. Baron ◽  
B. De Salvo ◽  
P. Mur
Keyword(s):  
Silicon Nanocrystals ◽  
Batch Reactor ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Oxide Surface ◽  
Growth Step ◽  
Step Process ◽  
Pressure Chemical ◽  
Higher Temperature ◽  
Size Dispersion

ABSTRACTNanocrystal memories are widely invoked as potential solutions to overcome the scaling limitations of conventional FLASH memories beyond the 80nm technology node. In this study, the deposition of uniform silicon nanocrystals has been developed and optimized in a commercially available vertical furnace, an A400 from ASM.It has been shown that low pressure chemical vapor deposition (LPCVD) of nanocrystals is feasible in a batch reactor but with a bad size dispersion of the silicon nanocrystals. To improve the size dispersion of the nanocrystals, a novel 2-step process with silane was introduced. In the conventional 1-step process, the oxide surface is exposed to silane at the same partial pressure and temperature during both nucleation and growth of the silicon nanocrystals. In this novel 2-step process, the surface is first exposed briefly to silane at a higher temperature (580–600°C) and following that, the temperature is lowered to allow selective growth on the existing silicon nuclei over the oxide surface. With such an approach, the nucleation step can be separated from the growth step and consequently the size dispersion can be improved by 50%.

Modeling of Silicon Nanodots Nucleation and Growth Deposited by LPCVD on SiO2 : From Molecule/surface Interactions to Reactor Scale Simulations

2006 ◽  
Vol 959 ◽  
Author(s):  
Ilyes Zahi ◽  
Hugues Vergnes ◽  
Brigitte Caussat ◽  
Alain Esteve ◽  
Mehdi Djafari Rouhani ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Deposition Time ◽  
Chemical Vapor ◽  
Surface Interactions ◽  
Nucleation And Growth ◽  
High Dilution ◽  
First Results ◽  
Pressure Chemical ◽  
Molecule Surface

ABSTRACTWe present first results combining models at continuum and atomistic (DFT) levels to improve understanding of key mechanisms involved in silicon nanodots (NDs) synthesis on SiO2 by Low Pressure Chemical Vapor Deposition (LPCVD) from silane SiH4. In particular, by simulating an industrial LPCVD reactor using the CFD code Fluent, we find that the deposition time could be increased and then the reproducibility and uniformity of NDs deposition could be improved when highly diluting silane in a carrier gas. A consequence of this high dilution seems to be that the contribution to deposition of unsaturated species such as silylene SiH2 highly increases. This result is important since our first DFT calculations have shown that silicon chemisorption on silanol Si-OH or siloxane Si-O-Si bonds present on SiO2 substrates could only proceed from silylene (and probably from other unsaturated species). The silane saturated molecule could only contribute to NDs growth, i.e. silicon chemisorption on already deposited silicon bonds. Increasing silylene contribution to deposition in highly diluting silane could then also exalt silicon nucleation on SiO2 substrates and then increase NDs density.

A Study of Nucleation and Growth in MOCVD: The Growth of Thin Films of Alumina

2000 ◽  
Vol 648 ◽  
Author(s):  
M.P. Singh ◽  
S. Mukhopadhayay ◽  
Anjana Devi ◽  
S.A. Shivashankar
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Secondary Ion Mass Spectrometry ◽  
Film Growth ◽  
Depth Profiling ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Cross Sectional ◽  
Alumina Films ◽  
Pressure Chemical

AbstractWe have studied the nucleation and growth of alumina by metalorganic chemical vapor deposition (MOCVD). The deposition of alumina films was carried out on Si(100) in a horizontal, hot-wall, low pressure chemical vapor deposition (CVD) reactor, using aluminum acetylacetonate{Al(acac)3}as the CVD precursor. We have investigated growth of alumina films as a function of different CVD parameters such as substrate temperature and total reactor pressure during film growth. Films were characterized by optical microscopy, X-ray diffractometry (XRD), scanning electron microscopy (SEM), cross-sectional SEM, and secondary ion mass spectrometry (SIMS) compositional depth profiling. The chemical analysis reveals that the carbon is present throughout the depth of the films.

Control of Silicon Quantum Dots nucleation and growth by CVD

2002 ◽  
Vol 737 ◽  
Author(s):  
F. Mazen ◽  
T. Baron ◽  
J. M. Hartmann ◽  
M. N. Semeria ◽  
G. Brémond
Keyword(s):  
Quantum Dots ◽  
Nucleation And Growth ◽  
Process Conditions ◽  
Silicon Quantum Dots ◽  
Growth Step ◽  
Oh Groups ◽  
Nucleation Sites ◽  
Experimental Parameters ◽  
Size Dispersion ◽  
New Si

ABSTRACTTo be successfully integrated in nano-electronics devices, silicon quantum dots (Si-QDs) density, density uniformity, size and size dispersion must be controlled with a great precision. Nanometric size Si-QDs can be deposited on insulators by SiH4 CVD. Their formation includes two steps : nucleation and growth. We study the experimental parameters which influence each step in order to improve the control of the Si-QDs morphology.We show that the nucleation step is governed by the reactivity of the substrate with the Si precursors. On SiO2, OH groups are identified as nucleation sites. By controlling the OH density on the SiO2 surface, we can monitor the Si-QDs density on more than one decade for the same process conditions. Moreover, Si-QDs density as high as 1.5 1012 /cm2 can be obtained. On the contrary, the growth step depends on process conditions. By modifying the gas phase composition, i.e by using SiH2Cl2 as Si precursor, we can grow the nuclei already formed during the nucleation step without formation of new Si-QDs. We discuss the advantages of this process to improve the control of the Si-QDs size and limit the size dispersion.

Grain size, Grain Uniformity, and (111) Texture Enhancement by Solid-phase Crystallization of F- and C-implanted SiGe Films

2000 ◽  
Vol 15 (7) ◽  
pp. 1630-1634 ◽  
Author(s):  
A. Rodríguez ◽  
J. Olivares ◽  
C. González ◽  
J. Sangrador ◽  
T. Rodríguez ◽  
...  
Keyword(s):  
Grain Size ◽  
Vapor Deposition ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solid Phase Crystallization ◽  
Grain Sizes ◽  
Pressure Chemical ◽  
Film Microstructure ◽  
Si Films ◽  
Size Dispersion

The crystallization kinetics and film microstructure of poly-SiGe layers obtained by solid-phase crystallization of unimplanted and C- and F-implanted 100-nm-thick amorphous SiGe films deposited by low-pressure chemical vapor deposition on thermally oxidized Si wafers were studied. After crystallization, the F- and C-implanted SiGe films showed larger grain sizes, both in-plane and perpendicular to the surface of the sample, than the unimplanted SiGe films. Also, the (111) texture was strongly enhanced when compared to the unimplanted SiGe or Si films. The crystallized F-implanted SiGe samples showed the dendrite-shaped grains characteristic of solid-phase crystallized pure Si. The structure of the unimplanted SiGe and C-implanted SiGe samples consisted of a mixture of grains with well-defined contour and a small number of quasi-dendritic grains. These samples also showed a very low grain-size dispersion.

Growth and In-line Characterization of Silicon Nanodots Integrated in Discrete Charge Trapping Non-volatile Memories

2011 ◽  
Vol 1337 ◽  
Author(s):  
J. Amouroux ◽  
V. Della Marca ◽  
E. Petit ◽  
D. Deleruyelle ◽  
M. Putero ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Chemical Vapor ◽  
Charge Trapping ◽  
Critical Dimension ◽  
Growth Surface ◽  
Oxide Surface ◽  
Pressure Chemical ◽  
Deposition Uniformity ◽  
Average Size

ABSTRACTNon-Volatile Memories (NVM) integrating silicon nanodots (noted SDs) are considered as an emerging solution to extend Flash memories downscaling. In this alternative memory technology, silicon nanocrystals act as discrete traps for injected charges.Si-dots were grown by Low Pressure Chemical Vapor Deposition (LPCVD) on top of tunnel oxide. Depending on the pre-growth surface treatment, tunnel oxide surface may present either siloxane or silanol groups. SDs deposition relies on a 2–steps process: nucleation by SiH4 and selective growth with SiH2Cl2.In a context of technological industrialization, it is of primary importance to develop in-line metrology tools dedicated to Si-dots growth process control. Hence, silicon-dots were observed in top view by using an in-line Critical Dimension Scanning Electron Microscopy CDSEM and their average size and density were extracted from image processing. In addition, Haze measurement, generally used for bare silicon surface characterization, was customized to quantify Si-dots deposition uniformity over the wafer. Finally, Haze value was correlated to Si nanodots density and size determined by CDSEM.

scholarly journals Formation of silicon nanocrystals by thermal annealing of low-pressure chemical-vapor deposited amorphous SiNx (x=0.16) thin films

2013 ◽  
Vol 16 (6) ◽  
pp. 1849-1852 ◽  
Author(s):  
Hakim Haoues ◽  
Hachemi Bouridah ◽  
Mahmoud Riad Beghoul ◽  
Farida Mansour ◽  
Riad Remmouche ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Annealing ◽  
Silicon Nanocrystals ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Chemical Vapor Deposited ◽  
Pressure Chemical
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