Ar+ Implantation Effects on Polycrystalline Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
J. H. Lee ◽  
C. W. Hwang ◽  
J. E. Shin ◽  
Y. S. Jin ◽  
S. B. Mah
Keyword(s):  
Solid Phase ◽  
Chemical Vapor ◽  
Implantation Dose ◽  
Structural Deformation ◽  
Implantation Technique ◽  
Polycrystalline Thin Films ◽  
Average Grain Size ◽  
Pressure Chemical ◽  
Thin Polycrystalline ◽  
Si Films

AbstractThe solid phase crystallization behavior of argon ion (Ar+) implanted very thin polycrystalline silicon (poly-Si) films has been investigated. Poly-Si films of 500Å thickness were deposited at 625°C by low pressure chemical vapor deposition (LPCVD). The films were amorphized by Ar+ implantation with 7 ° tilt angle. The amount of ions implanted was varied from 2.0 × 1013 cm-2 to 1.2 × 1015 cm-2 and the acceleration voltages from 40KeV to 120KeV. The films were recrystallized by furnace annealing at 580°C for 48 hours in N2 atmosphere, followed by 1000°C annealing The crystallinity of the recrystallized Si films and the distribution of the argon atoms in the film were investigated. It was found that the crystallinity strongly depended on the Ar+ implantation dose. The average grain size of Ar+ implanted film was about 0.25μm, which was smaller than that of Si+ implanted film of the same dose, 0.45μm. Ar atoms retarded the grain growth rate during the annealing process and the excess Ar atoms in Si films were segregated at the surface of silicon films after 1000°C annealing Poly-Si thin film transistors (TFTs) were fabricated at high temperature using Ar+ implantation technique. Remarkable electrical characteristics (Ids- Vgs) were obtained such as an electron mobility of 35 cm2/V.s, which was attributed to the enhancement of crystallinity by Ar+ implantation. But, segregated Ar atoms near the interface would give rise to structural deformation and crystalline defects which can act as the scattering and’ trapping centers for carriers.

Polycrystalline Silicon Films Formed by Solid-Phase Crystallization of Amorphous Silicon: the Substrate Effects on Crystallization Kinetics and Mechanism

1996 ◽  
Vol 424 ◽  
Author(s):  
Y.-H. Song ◽  
S.-Y. Kang ◽  
K. I. Cho ◽  
H. J. Yoo ◽  
J. H. Kim ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solid Phase Crystallization ◽  
Substrate Effects ◽  
Random Nucleation ◽  
Pressure Chemical ◽  
Si Films ◽  
Polycrystalline Silicon Films ◽  
Induced Crystallization

AbstractThe substrate effects on the solid-phase crystallization of amorphous silicon (a-Si) have been extensively investigated. The a-Si films were prepared on two kinds of substrates, a thermally oxidized Si wafer (SiO2/Si) and a quartz, by low-pressure chemical vapor deposition (LPCVD) using Si2H6 gas at 470 °C and annealed at 600 °C in an N2 ambient for crystallization. The analysis using XRD and Raman scattering shows that crystalline nuclei are faster formed on the SiO2/Si than on the quartz, and the time needed for the complete crystallization of a-Si films on the SiO2/Si is greatly reduced to 8 h from ˜15 h on the quartz. In this study, it was first observed that crystallization in the a-Si deposited on the SiO2/Si starts from the interface between the a-Si film and the thermal oxide of the substrate, called interface-induced crystallization, while random nucleation process dominates on the quartz. The very smooth surface of the SiO2/Si substrate is responsible for the observed interface-induced crystallization of a-Si films.

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.

Modifying Crystallographic Orientations of Polycrystalline Si Films Using Ion Channeling

1984 ◽  
Vol 35 ◽  
Author(s):  
K. T-Y. Kung ◽  
R. B. Ivepson ◽  
R. Reif
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Silicon On Insulator ◽  
Furnace Annealing ◽  
Ion Channeling ◽  
Amorphous Substrates ◽  
Pressure Chemical ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTPolycrystalline silicon films 4800 Å thick deposited via low pressure chemical vapor deposition on oxidized silicon wafers have been amorphized by silicon ion implantation and subsequently recrystallized at 700°C. Due to channeling of the ions through grains whose <110> axes were sufficiently parallel to the beam, these grains survived the implantation step and acted as seed crystals for the solid-phase epitaxial regrowth of the film. This work suggests the feasibility of combining ion implantation and furnace annealing to generate large-grain, uniformly oriented polycrystal1ine films on amorphous substrates. It is a potential low-temperature silicon-on-insulator technology.

scholarly journals Controlled Deposition of Lead Iodide and Lead Chloride Thin Films by Low-Pressure Chemical Vapor Deposition

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1208
Author(s):  
Siphelo Ngqoloda ◽  
Christopher J. Arendse ◽  
Theophillus F. Muller ◽  
Siphesihle S. Magubane ◽  
Clive J. Oliphant
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Lead Chloride ◽  
Lead Iodide ◽  
Cvd Method ◽  
Average Grain Size ◽  
Pressure Chemical ◽  
Lead Halide

Lead halide thin films, such as lead iodide (PbI2) and lead chloride (PbCl2), are used as precursor films for perovskite preparation, which is frequently achieved by vacuum thermal evaporation but rarely by the low-pressure chemical vapor deposition (CVD) method. Here, we report on the deposition of PbI2 and PbCl2 thin films on glass substrates by employing the low-pressure CVD method. The effect of the substrate temperature on the structure and morphology of the lead halide films is investigated. Crystalline films were realized for both lead halides, with PbI2 films showing high texture compared to the reduced texture of the PbCl2 films. Large lateral grain sizes were observed for the PbI2 films with a flat platelet grain morphology and an average grain size up to 734.2 ± 144.8 nm. PbCl2 films have columnar grains with an average grain size up to 386.7 ± 119.5 nm. The PbI2 films showed a band gap of about 2.4 eV, confirming its semiconducting properties, and the PbCl2 had a wide band gap of 4.3 eV, which shows the insulating properties of this material.

Stress Induced During the Solid-phase Crystallization of Amorphous Silicon Deposited by LPCVD

1995 ◽  
Vol 403 ◽  
Author(s):  
T. Mohammed-Brahim ◽  
K. Kis-Sion ◽  
D. Briand ◽  
M. Sarret ◽  
F. Lebihan ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Solid Phase ◽  
Chemical Vapor ◽  
In Situ Monitoring ◽  
Crystallization Time ◽  
Solid Phase Crystallization ◽  
Pressure Chemical ◽  
Hall Effect Measurements ◽  
Deposition Techniques

AbstractThe Solid Phase Crystallization (SPC) of amorphous silicon films deposited by Low Pressure Chemical Vapor phase Deposition (LPCVD) using pure silane at 550'C was studied by in-situ monitoring the film conductance. The saturation of the conductance at the end of the crystallization process is found transient. The conductance decreases slowly after the onset of the saturation. This degradation is also observed from other analyses such as ellipsometry spectra, optical transmission and Arrhenius plots of the conductivity between 250 and 570K. Hall effect measurements show that the degradation is due to a decrease of the free carrier concentration n and not to a decrease of the mobility. This indicates a constant barrier height at the grain boundaries. The decrease of n is then due to a defect creation in the grain. Hence, whatever the substrate used, an optimum crystallization time exists. It depends on the amorphous quality film which is determined by the deposition techniques and conditions and on the crystallization parameters.

STRUCTURAL AND OPTICAL PROPERTIES OF NANOCRYSTALLINE SILICON FILMS DEPOSITED AT 150°C

2002 ◽  
Vol 16 (01n02) ◽  
pp. 219-226 ◽  
Author(s):  
ATIF MOSSAD ALI ◽  
YASUHIKO SAKAI ◽  
NOBORU ADACHI ◽  
TAKAO INOKUMA ◽  
YOSHIHIRO KURATA ◽  
...  
Keyword(s):  
Optical Properties ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Close Correlation ◽  
Nanocrystalline Silicon ◽  
Nanocrystalline Phase ◽  
Structural And Optical Properties ◽  
Average Grain Size ◽  
Si Films ◽  
Two Peaks

Nanocrystalline silicon (nc-Si) films were deposited by plasma-enhanced chemical vapor deposition from a SiH 4- H 2 gas mixture. The structural and optical properties of nc-Si films were examined by changing the flow rates of a H 2 gas or a SiF 4 gas diluted by He. The structural change from an amorphous to a nanocrystalline phase was found at H 2 flow rate ([ H 2]) higher than 3 sccm under [ SiF 4/ He ] = 0 sccm and/or by adding SiF 4/ He under [ H 2] = 0 sccm . However, under [ H 2] = 3 sccm, the maximum crystallinity (crystalline volume fraction, ρ) was observed at around [ SiF 4/ He ] = 2 sccm . The photoluminescence exhibited two peaks at around 1.7 eV and 2.2 - 2.3 eV. The first 1.7-eV-peak may be related to nanocrystallites in nc-Si films and the origin of another 2.2 - 2.3-eV-peak is not clear. Thus, hydrogen and fluorine appear to play different role in the crystallization process. In addition, under [ H 2] = 0 sccm , we found a close correlation among the increases in the ρ and the average grain size values and the SiH 2 density with increasing [ SiF 4/ He ].

Stress Effects on Nanocrystal Formation by Ni-Induced Crystallization of Amorphous Si

2003 ◽  
Vol 762 ◽  
Author(s):  
Yaocheng Liu ◽  
Michael D. Deal ◽  
Mahmooda Sultana ◽  
James D. Plummer
Keyword(s):  
Low Temperature ◽  
Integrated Circuits ◽  
Crystallization Rate ◽  
Chemical Vapor ◽  
Sputtering Deposition ◽  
Si Nanocrystals ◽  
Pressure Chemical ◽  
Amorphous Si ◽  
Si Films ◽  
Induced Crystallization

AbstractMetal-induced crystallization (MIC) of amorphous Si is gaining increased interest because of its potential use for low-temperature fabrication of integrated circuits. In this work, the MIC technique was used to make Si nanocrystals and the effects of stress on the crystallization were studied. Amorphous Si films were deposited onto the Si substrate with thermal oxides on top by low-pressure chemical vapor deposition (LPCVD) and then patterned into nanoscale pillars by electron beam lithography and reactive ion etching. A conformal low-temperature oxide (LTO) layer was deposited to cover the pillars, followed by an anisotropic etch back to form a spacer, leaving only the top surface of the pillars exposed to the 5 nm Ni sputtering deposition afterwards. An HF dip was used to partially remove the LTO spacers on the pillars, leading to different LTO thicknesses on different samples. These samples were then annealed to crystallize the amorphous Si pillars, forming Si nanocrystals. Transmission electron microscope (TEM) observations after anneal found a clear dependence of the crystallization rate on the pillar size as well as the LTO thickness. The crystallization rate was lower for pillars with thicker LTO spacers, while for the same LTO thickness the crystallization rate was lower for pillars with narrower width. A model based on the stress in the pillars is proposed to explain this dependence. This model suggests some methods to control the nickel-induced crystallization process and achieve higher quality Si nanocrystals.

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