Effects of Germanium on Grain size and surface roughness of the solid phase crystallized polycrystalline Si1−xGex films

1996 ◽  
Vol 424 ◽  
Author(s):  
Jin-Won Kim ◽  
Myung-Kwan Ryu ◽  
Tae-Hoon Kim ◽  
Ki-Bum Kim ◽  
Sang-Joo Kim
Keyword(s):  
Activation Energy ◽  
Surface Roughness ◽  
Grain Size ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Germanium Content ◽  
Capping Layer ◽  
Before And After ◽  
Pressure Chemical ◽  
The Difference

AbstractSi1−xGex (x≤0.5) films were deposited by using Si2H4 and GeH4 source gases in a low pressure chemical vapor deposition (LPCVD). The deposition temperature was varied from 375 °C for Si0.5Ge0.5 to 450 °C for Si film in order to deposit amorphous Si1−xGex films and the deposition pressure was about 1 Torr. The grain size of polycrystalline Si1−xGex films made by solid phase crystallization (SPC) decreases with germanium content in the films, and the activation energy obtained from the dependence of grain size on annealing temperature was 0.4 eV for Si and 0.45 eV for Si0 69Ge0.31. From obtaining a similar activation energy irrespective of Ge content in the film, the decrease of grain size with germanium content is attributed to the difference of the asdeposited film conditions. The surface roughness of Si1−xGex films investigated by atomic force microscope (AFM) increases with germanium content in the film before and after SPC. For instance, the root-mean square (rms) values of the surface roughness of the as-deposited Si and Si0.5Ge0.5 films were 2.3 and 17 Å, while those values were increased to 2.6 and 41 Å, respectively, after SPC. In order to reduce the surface roughness of Si0.5Ge0.5 film, we have deposited a thin Si capping layer on top of the Si1−xGex layer and identified that this capping layer effectively reduces the increase of surface roughness after SPC.

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.

Performance of thin film Transistors on Unhydrogenated In-Situ Doped Polysilicon films Obtained by Solid Phase Crystallization

1997 ◽  
Vol 471 ◽  
Author(s):  
K. Mourgues ◽  
F. Raoult ◽  
L. Pichon ◽  
T. Mohammed-Brahim ◽  
D. Briand ◽  
...  
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Thin Film Transistors ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Pressure Chemical ◽  
Polysilicon Films ◽  
The Difference

ABSTRACTLow Temperature Unhydrogenated in-situ doped polysilicon Thin Film Transistors (LTUTFT) are made through two types of four-mask aluminium gate process. Silicon layers are elaborated by a Low Pressure Chemical Vapor Deposition (LPCVD) method and crystallized by a thermal annealing. Source and drain regions are in-situ doped. An Atmospheric Pressure Chemical Vapor Deposition (APCVD) silicon dioxide ensures the gate insulation. Two structures A and B are fabricated, the difference is that for sample B the undoped/doped polysilicon layer interface is suppressed.The structure of the polysilicon films is studied using Transmission Electron Microscopy (TEM) and Current-Voltage characteristics of both types of TFTs indicate electrical quality of the polysilicon films.The best electrical properties are obtained with the B type TFTs: a low threshold voltage (VT=1.2V), a low subthreshold slope (0.7 V/dec), a high On/Off state current ratio (107) for a drain voltage VDS= 1V, and a very high field effect mobility (≥100 cm2 /Vs). It is worth to notice that these good results are obtained without hydrogenation.

Quantitative Modelling of Nucleation Kinetics in Experiments for Poly-Si Growth on Sio2 by Hot-Wire Chemical Vapor Deposition

2001 ◽  
Vol 664 ◽  
Author(s):  
Maribeth Swiatek ◽  
Jason K. Holt ◽  
Harry A. Atwater
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Nucleation Density ◽  
Hot Wire ◽  
Nucleation Kinetics ◽  
Temperature Dependent ◽  
Cluster Density

ABSTRACTWe apply a rate-equation pair binding model of nucleation kinetics [1] to the nucleation of Si islands grown by hot-wire chemical vapor deposition on SiO2 substrates. Previously, we had demonstrated an increase in grain size of polycrystalline Si films with H2 dilution from 40 nm using 100 mTorr of 1% SiH4 in He to 85 nm with the addition of 20 mTorr H2. [2] This increase in grain size is attributed to atomic H etching of Si monomers rather than stable Si clusters during the early stages of nucleation, decreasing the nucleation density. Atomic force microscopy (AFM) measurements show that the nucleation density increases sublinearly with time at low coverage, implying a fast nucleation rate until a critical density is reached, after which grain growth begins. The nucleation density decreases with increasing H2 dilution (H2:SiH4), which is an effect of the etching mechanism, and with increasing temperature, due to enhanced Si monomer diffusivity on SiO2. From temperature-dependent measurements, we estimate the activation energy for surface diffusion of Si monomers on SiO2 to be 0.47 ± 0.09 eV. Simulations of the temperature-dependent supercritical cluster density lead to an estimated activation energy of 0.42 eV ± 0.01 eV and a surface diffusion coefficient prefactor of 0.1 ± 0.03 cm2/s. H2-dilution-dependent simulations of the supercritical cluster density show an approximately linear relationship between the H2 dilution and the etch rate of clusters.

Low pressure chemical vapor deposition of B-N-C-H films from triethylamine borane complex

1995 ◽  
Vol 10 (2) ◽  
pp. 320-327 ◽  
Author(s):  
R.A. Levy ◽  
E. Mastromatteo ◽  
J.M. Grow ◽  
V. Paturi ◽  
W.P. Kuo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Apparent Activation Energy ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Index Of Refraction ◽  
Arrhenius Behavior ◽  
Pressure Chemical

In this study, films consisting of B-N-C-H have been synthesized by low pressure chemical vapor deposition using the liquid precursor triethylamine borane complex (TEAB) both with and without ammonia. When no NH3 is present, the growth rate was observed to follow an Arrhenius behavior in the temperature range of 600 to 800 °C with an apparent activation energy of 11 kcal/mol. A linear dependence of growth rate is observed as a function of square root of flow rate for the TEAB range of 20 to 60 sccm, indicating that the reaction rate is controlled by the adsorption of borane. The addition of NH3 to TEAB had the effect of lowering the deposition temperature down to 300 °C and increasing the apparent activation energy to 22 kcal/mol. Above 650 °C, the carbon concentration of the deposits increased significantly, reflecting the breakup of the amine molecule. X-ray diffraction measurements indicated the films to be in all cases amorphous. Infrared spectra of the films showed absorption peaks representing the vibrational modes of B-N, B-N-B, B-H, and N-H. The index of refraction varied between 1.76 and 2.47, depending on composition of the films. Films deposited with no NH3 above 700 °C were seen to be compressive while films below that temperature were tensile. In the range of 350 to 475 °C, the addition of NH3 to TEAB resulted in films that were mildly tensile, while below 325 °C and above 550 °C, the films were found to be compressive. Both the hardness and Young's modulus of the films decreased with higher temperatures, reflecting the influence of the carbon presence.

Influence of Abrasive on Planarization Grinding Based on the Cluster Magnetorheological Effect

2011 ◽  
Vol 325 ◽  
pp. 542-547
Author(s):  
Qiu Sheng Yan ◽  
Jie Wen Yan ◽  
Jia Bin Lu ◽  
Wei Qiang Gao ◽  
Min Li
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Optical Glass ◽  
Removal Rate ◽  
Mr Fluid ◽  
Grinding Method ◽  
Magnetorheological Effect ◽  
The Difference ◽  
Mr Effect

A new planarization grinding method based on the cluster magnetorheological (MR) effect is presented to grind optical glass in this paper. Some process experiments were conducted to reveal the influence of the species and granularity and content of the abrasive materials in the MR fluid on the machining effect, furthermore, the machining characteristic of grinded surface was studied. The results indicate that the abrasive influences definitively on machining effect of this planarization grinding method based on the cluster MR-effect. Under the certain experiment condition, with the content of the abrasive 10% and grain size 800# of SiC, best machining effect can be achieved. The difference species of abrasive results in various machining effects. As for the removal rate of K9 optical glass: abrasive CeO2 is the best, the Al2O3 is the second and the SiC is the worst. While the surface roughness: abrasive SiC is the lowest，the Al2O3 is the second and CeO2 is the highest.

Effects of Process Parameters on Graphene Growth Via Low-Pressure Chemical Vapor Deposition

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Byoungdo Lee ◽  
Weishen Chu ◽  
Wei Li
Keyword(s):  
Grain Size ◽  
Chemical Vapor Deposition ◽  
Process Parameters ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Growth ◽  
Low Pressure ◽  
Large Set ◽  
Graphene Growth ◽  
Pressure Chemical

Abstract Graphene has attracted enormous research interest due to its extraordinary material properties. Process control to achieve high-quality graphene is indispensable for graphene-based applications. This research investigates the effects of process parameters on graphene quality in a low-pressure chemical vapor deposition (LPCVD) graphene growth process. A fractional factorial design of experiment is conducted to provide understanding on not only the main effect of process parameters, but also the interaction effect among them. Graphene quality including the number of layers and grain size is analyzed. To achieve monolayer graphene with large grain size, a condition with low CH4–H2 ratio, short growth time, high growth pressure, high growth temperature, and slow cooling rate is recommended. This study considers a large set of process parameters with their interaction effects and provides guidelines to optimize graphene growth via LPCVD focusing on the number of graphene layers and the grain size.

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.

Improvement of Grain-Growth and Surface Roughness in Laser-Crystallized Polycrystalline Silicon Films

1997 ◽  
Vol 472 ◽  
Author(s):  
H.-S. Choi ◽  
C.-M. Park ◽  
J.-H. Jeon ◽  
B.-H. Min ◽  
M.-K. Han
Keyword(s):  
Surface Roughness ◽  
Grain Growth ◽  
Polycrystalline Silicon ◽  
Treatment Time ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solidification Process ◽  
Laser Crystallization ◽  
Sem Images ◽  
Radical Treatment

ABSTRACTThe effects of nitrogen-radical treated amorphous silicon (a-Si) films on laser-crystallization behavior have been studied for the improvement of the grain-growth and the surface roughness. The radical treatments were performed by the rf (13.56 MHz) plasma-enhanced-chemical-vapor-deposition (PECVD) system with N2 gas before the laser-crystallization. The grain-size of the laser-crystallized polycrystalline silicon (poly-Si) film with 600 seconds of radical-treatment time was remarkably increased by the relaxation of solidification process caused by the possible evolution of solid phase SiNx compounds which shows the low thermal conductivity. The electrical conductivity at 30 °C was rather lager value of 3×10-5 Ω-1cm-1 than 1×10-5 Ω-1cm-1 of poly-Si without radical treatment, while the highly resistive SiNx compounds were formed. From the SEM images, the surface roughness was also improved by the selective etching of the 5%-water-diluted hydrofluoric (HF) acid on the grain boundaries which the SiNx compounds were well segregated into during the laser-crystallization.

Research on the Effects of Roughness on the Tactile Properties of Rice Straw Particleboard Surface

2020 ◽  
Vol 12 (6) ◽  
pp. 795-801 ◽  
Author(s):  
Xian-Qing Xiong ◽  
Ying-Ying Yuan ◽  
Yi-Ting Niu ◽  
Liang-Ting Zhang
Keyword(s):  
Surface Roughness ◽  
Rice Straw ◽  
Interior Design ◽  
Roughness Parameter ◽  
Chemical Properties ◽  
Mesh Size ◽  
Design Guidelines ◽  
Before And After ◽  
The Difference ◽  
Parameter Values

To explore the effects of roughness on the tactile properties of rice straw particleboard (RSP), the surface roughness and psychological tactile and visual experiments were conducted for RSP substrates with 0.76 g/cm3 and 0.55 g/cm3 densities after sanding with sandpaper (mesh 180#, 360#, and 600#). The effects of different sandpaper types, sanding time, and density of RSP on the surface roughness were analyzed. The experimental results are as follows. The sanding treatment had significant influence on the surface roughness characterization parameters Ra and Rpv of the RSP specimens. Surface roughness differences between the 180# and 360# mesh-prepared samples were obvious. The tactile and visual psychological values of the 360# and 600# mesh-sanded specimens were higher, and the psychological quantities of untreated and 180# mesh-sanded specimens were lower. After comparing the samples with sanding treatment of sandpaper 0∼180#, the change in surface roughness of RSP with a density of 0.76 g/cm3 was smaller than that of the specimen with a density of 0.55 g/cm3. The psychological quantity difference of RSP specimens with a density of 0.55 g/cm3 was evident. When the sanding time was 1 min., the values of the roughness characterization parameters Ra and Rpv increased slightly. After 3 min. sanding, the Ra and Rpv values stabilized. When the sanding time was 5 min, the roughness was essentially unchanged. With the change in sanding time, the measured values of the tactile psychological quantity varied greatly and the measured values of the visual psychology were very close. For the RSP substrates with higher density, the surface roughness was less after sanding with a smoother surface and better tactile properties. There were significant differences between the surface roughness of the RSPs before and after sanding. After manual sanding over the same time span, the surface roughness evaluation parameter values decreased with an increase of mesh size of the sandpaper, and the tactile properties were improved. The longer the sanding time, the smaller the difference in the surface roughness parameter values, and the smaller the difference between the tactile psychological quantity and the visual psychological quantity. To expand the research scope of RSP products, this study investigates not only the physical and chemical properties but also the subjective feelings when using the RSP products. This will provide analytical methods and design guidelines for the consideration of environmental factors in furniture and interior design.

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.

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