Temperature Dependence of Structure, Transport and Growth of Microcrystalline Silicon: Does Grain Size Correlate with Transport?

1989 ◽  
Vol 149 ◽  
Author(s):  
C. C. Tsai ◽  
G. B. Anderson ◽  
B. Wacker ◽  
R. Thompson ◽  
C. Doland
Keyword(s):  
Grain Size ◽  
Temperature Dependence ◽  
Chemical Vapor ◽  
Degree Of Crystallinity ◽  
Structural Defects ◽  
Thermal Cvd ◽  
Normal Behavior ◽  
Average Grain Size ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTThe temperature dependence of the growth, structure and transport of plasma-deposited microcrystalline and polycrystalline silicon films have been investigated over the temperature range of 50°C to 350°C. While low substrate temperature yields small grain sizes as expected, high temperature also tends to suppress the grain growth, contrary to the normal behavior observed in thermal CVD (chemical vapor deposition) where crystallinity grows with temperature. In fact, the highest temperature of 350°C corresponds to the lowest degree of crystallinity. Furthermore, it is found that, unlike the polycrystalline Si prepared by thermal CVD, the transport properties of the Si films do not necessarily correlate with the grain size or structural defects. While the largest average grain size of 800–1000 Å was obtained at 200°C, the highest Hall mobility and conductivity were obtained near 250°C, which corresponds to a material with smaller grains and an abundance of voids.

Polycrystalline Silicon Films on SiO2 Substrate Treated by Excimer Laser Annealing

2013 ◽  
Vol 750-752 ◽  
pp. 946-951
Author(s):  
Chun Yan Duan ◽  
Bin Ai ◽  
Rong Xue Li ◽  
Chao Liu ◽  
Jian Jun Lai ◽  
...  
Keyword(s):  
Grain Size ◽  
Excimer Laser ◽  
Polycrystalline Silicon ◽  
Laser Annealing ◽  
Laser Energy ◽  
Chemical Vapor ◽  
Excimer Laser Annealing ◽  
Before And After ◽  
Si Films ◽  
Polycrystalline Silicon Films

Selected area laser-annealed polycrystalline silicon (p-Si) thin films were prepared by a 248 nm excimer laser. 1 μm thick p-Si films with grain size less than 100 nm were deposited on SiO2substrate by chemical vapor deposition using atmospheric pressure (APCVD). Grain sizes before and after annealing was examined by scanning electron microscopy (SEM) and the mechanism of grain growth was discussed in detail. The maximum grain size of a selected area laser-annealed p-Si film can be increased from 100 nm up to 2.9 μm on SiO2substrate by using appropriate laser energy densities. It indicated that silicon grains in laser-annealed regions had grown up competitively with three stages.

Properties and Application of Undoped Hydrogenated Microcrystalline Silicon Thin Films

1989 ◽  
Vol 149 ◽  
Author(s):  
J. Kanicki ◽  
E. Hasan ◽  
D. F. Kotecki ◽  
T. Takamori ◽  
J. H. Griffith
Keyword(s):  
Grain Size ◽  
Deposition Temperature ◽  
Etch Rate ◽  
Chemical Vapor ◽  
Microcrystalline Silicon ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Average Grain Size ◽  
Structural And Electrical Properties ◽  
Deposition Conditions

ABSTRACTDevice quality undoped hydrogenated microcrystalline silicon has been prepared by plasma enhanced chemical vapor deposition under different conditions. The dependence of physical, chemical, structural, and electrical properties on the deposition conditions has been investigated. Conductive (conductivity above 10−3Ω−1 cm−1) and resistive (conductivity around 10−9Ω−1cm−1) layers having approximately the same grain size, at a given substrate temperature, have been deposited between 200 and 500°C at two different hydrogen dilutions. Independently of the hydrogen dilution, the average grain sized is dependent on the deposition temperature and the film thickness; and a maximum average grain size of about 40 nm has been achieved for a thick film deposited at 500°C. The density of paramagnetic defects also increases with increasing deposition temperature, which indicates that more dangling bond defects are introduced as the total area of the grain boundaries increases. The etch rate decreases with increasing deposition temperature, and for the films deposited at 250 and 500°C the etch rate has been measured to be 6.6 and 2.7 nm/min, respectively. Thin film transistors incorporating a microcrystalline channel have been fabricated and evaluated. The best device had the following properties: field effect mobility, threshold voltage, and on/off current ratio of about 0.8 cm2/V sec, below 5 V, and around 106, respectively.

Deposition of Amorphous and Microcrystalline Si,C Alloy Thin Films by a Remote Plasma-Enhanced Chemical-Vapor Deposition Process

1991 ◽  
Vol 219 ◽  
Author(s):  
C. Wang ◽  
G. Lucovsky ◽  
R. J. Nemanich
Keyword(s):  
Raman Spectra ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Degree Of Crystallinity ◽  
Microcrystalline Silicon ◽  
Electrical And Optical Properties ◽  
Silicon Carbon ◽  
Infrared Measurements ◽  
Si Films ◽  
The Degree Of Crystallinity

ABSTRACTWe have extended the remote PECVD process to the deposition of intrinsic and doped, amorphous and microcrystalline silicon, carbon alloy films, a-Si,C:H and μc-Si,C, respectively. The electrical and optical properties of a-Si,C:H deposited by remote PECVD are comparable to those of films deposited by the glow discharge or GD process. The degree of crystallinity in the μc-Si,C alloys, as determined from the relative intensities of crystalline and amorphous features in the Raman spectra, is lower than that of μc-Si films deposited under comparable deposition conditions. The Raman spectra indicate that the crystallites in the μc-Si,C alloys are Si, while the infrared measurements establish that the intervening amorphous component is an a-Si,C:H alloy.

Excimer Lasbr Induced Crystallization of thin Amorphous Si Films on SiO2: Implications of Crystallized Microstructures for Phase Transformation Mechanisms

1992 ◽  
Vol 283 ◽  
Author(s):  
H. J. Kim ◽  
James S. Im ◽  
Michael O. Thompson
Keyword(s):  
Grain Size ◽  
Energy Density ◽  
Laser Energy ◽  
High Energy ◽  
High Energy Density ◽  
Laser Energy Density ◽  
Single Shot ◽  
Average Grain Size ◽  
Si Films ◽  
Density Regime

ABSTRACTUsing planar view transmission electron microscope (TEM) and transient reflectance (TR) analyses, we have investigated the excimer laser crystallization of amorphous silicon (a-Si) films on SiO2. Emphasis was placed on characterizing the microstructures of the single-shot irradiated materials, as a function of the energy density of the laser pulse and the temperature of the substrate. The dependence of the grain size and melt duration as a function of energy density revealed two major crystallization regimes. In the low energy density regime, the average grain size first increases gradually with increases in the laser energy density. In the high energy density regime, on the other hand, a very fine grained microstructure, which is relatively insensitive to variations in the laser energy density, is obtained. In addition, we have discovered that at the transition between these two regimes an extremely small experimental window exists, within which an exceedingly large grain-sized polycrystalline film is obtained. We suggest a liquid phase growth model for this phenomenon, which is based on the regrowth of crystals from the residual solid islands at the oxide interface.

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.

Afm/Tem Investigation of Low Temperature Polycrystalline Silicon Grown by ECR-CVD

1995 ◽  
Vol 406 ◽  
Author(s):  
H. L. Hsiao ◽  
K. C. Wang ◽  
L. W. Cheng ◽  
A. B. Yang ◽  
T. R. Yew ◽  
...  
Keyword(s):  
Low Temperature ◽  
Polycrystalline Silicon ◽  
Electron Cyclotron Resonance ◽  
Film Growth ◽  
Chemical Vapor ◽  
Plan View ◽  
3 Dimensional ◽  
High Resolution Tem ◽  
Si Films ◽  
Polycrystalline Silicon Films

AbstractThe polycrystalline silicon films were deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) with hydrogen dilution at 250°C and without any thermal annealing. The surface morphology and the microstructure of the poly-Si films are investigated by atomic force microscopy (AFM), plan-view transmission electron microscopy (TEM), crosssectional TEM and high resolution TEM (HRTEM). The low temperature poly-Si films deposited by ECR-CVD show a special leaf-like grain shape (plan-view) and an upside-down cone shape (3-dimensional view). The grains in the poly-Si films have preferred orientation of <112> and the longer side of the leaf-like grain is direction and the shorter side is direction. Lattice bending and interruption are found in the films. The arrangement of the atoms on the grains are well ordered, while atoms in the interfacial regions are randomly distributed. A simple grain formation model based on growth rate differences between different planes and etching effect can explain the film growth mechanism and the formation of the special grain geometry.

Effect of Temperature on the Microstructure and Electrical Conductivity of Microcrystalline Si Films

2017 ◽  
Vol 895 ◽  
pp. 28-32 ◽  
Author(s):  
Hua Cheng ◽  
Di Wang ◽  
Feng Li Li
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Substrate Temperature ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Gaseous Mixture ◽  
Chemical Vapor ◽  
Effect Of Temperature ◽  
Si Films ◽  
Resonance Plasma

Micro-Si films were deposited using Ar diluted SiH4 gaseous mixture by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD). The effects of the substrate temperature on microstructure and electrical conductivity of micro-Si film were investigated. The results show that, with the increasing of substrate temperature, crystallinity and grain size increased monotonously, of which a competing balance would determine the electrical conductivity of micro-Si films. Based on these results, relatively small grain size and appropriate crystallinity would be beneficial to improve the electrical properties of micro-Si films.

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 ].

¼c Silicon Thin Films Deposited by Remote Plasma Enhanced Chemical Vapor Deposition Process

1990 ◽  
Vol 192 ◽  
Author(s):  
C. Wang ◽  
G. N. Parsons ◽  
S. S. Kim ◽  
E. C. Buehler ◽  
R. J. Nemanich ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Substrate Material ◽  
Degree Of Crystallinity ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Type C ◽  
Si Films ◽  
P Type

ABSTRACTIn an earlier study, we deposited ¼c-Si thin films by reactive magnetron sputtering (RMS). Here we extend our studies to the deposition of both undoped and high conductivity N-type and P-type ¼c-Si thin films by a remote PECVD. We show that ¼c-Si films can be deposited by bringing hydrogen, H2, into the source gas mixtures. The H2 could introduced by either upstream in a He/H2 mixture and directly plasma excited, or downstream, and be remotely excited along with the silane, SiH4, feed gas. The degree of crystallinity is shown to depend on the hydrogen dilution, the substrate temperature and the substrate material.

Structure of Polycrystalline Silicon Films by Glow-Discharge Decomposition using SiH4/H2/SiF4 at Low Temperature

1999 ◽  
Vol 581 ◽  
Author(s):  
R. Tsuchida ◽  
M. Syed ◽  
T. Inokuma ◽  
Y. Kurata ◽  
S. Hasegawa
Keyword(s):  
Power Supply ◽  
Vapor Deposition ◽  
Local Structure ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
High Angle Boundary ◽  
Rf Power ◽  
Nanocrystalline Structures ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTFor poly-Si films prepared by a plasma-enhanced chemical vapor deposition, we examined the changes in the local structure caused by adding H2 and/or SiF4 in the SiH4 feed gases and by changing supplied rf power values. The conditions of low rf power supply, low H2 addition, and SiF4 addition allow formation of films with microcrystalline or nanocrystalline structures. In addition, the H2 or SiF4 addition was found to be effective in promotive growth of <111> or <110> grains, respectively. In such low crystallized films, it was suggested that high-angle boundary would be formed, leading to a decrease in the density of SiH2 and Si dangling bonds, and to an increase in g values.

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