On the Temperature Dependence of Resistivity of Polycrystalline Silicon Films

1987 ◽  
Vol 106 ◽  
Author(s):  
Mark S. Rodder ◽  
Dimitri A. Antoniadis
Keyword(s):  
Numerical Calculation ◽  
Polycrystalline Silicon ◽  
Amorphous Region ◽  
Defect States ◽  
Temperature Dependent ◽  
Step Process ◽  
Dependent Potential ◽  
Si Films ◽  
Polycrystalline Silicon Films ◽  
P Type

ABSTRACTIt is shown that the grain boundary (GB) in polycrystalline-silicon (poly-Si) films need not be modeled as a temperature-dependent potential barrier or as an amorphous region to explain the temperature (T) dependence of resistivity (ρ) in p-type poly-Si films at low T. Specifically, we consider that QB defect states allow for the tunneling component of current to occur by a two-step process. Incorporation of the two-step process in a numerical calculation of ρ vs. T results in excellent agreement with available data from 100 K to 300 K.

Si-H Vibration Only at 2000 CM-1 in Fully Polycrystalline Silicon Films Made by Hwcvd

2000 ◽  
Vol 609 ◽  
Author(s):  
J.K. Rath ◽  
R.E.I. Schropp
Keyword(s):  
Polycrystalline Silicon ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Amorphous Region ◽  
Hot Wire ◽  
Wire Temperature ◽  
Stretching Vibration ◽  
Closed Structure ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTThe Si-H vibration in IR spectra of our device quality poly-Si films grown by hot-wire chemical vapour deposition (HWCVD) made at low wire temperature (Tw=1800 °C) is at 2000 cm−1 whereas in a poly-Si film made at high wire temperature (Tw=1900 °C) both 2000 cm−1 vibrations as well as 2100 cm−1 are observed. On the other hand, the Raman spectra (probing the upper part of the film) of Si-H stretching vibration measured for both these samples show only 2000 cm-1 mode. XTEM micrographs of these films show that whereas the low Tw film has a structure made of closely packed crystalline columns, the high Tw film has conical crystalline structures with amorphous region between them. The crystal cones meet each other towards the top of the film and form a closed structure. This is confirmed by Raman spectrum at 520 cm−1. We attribute the 2100 cm−1 mode to the Si-H bonds at the surface of the cones touching the amorphous regions. The Si-H vibration shifts to 2000 cm-1 when the crystalline cones coalesce with each other, as is the case in the upper part of both types of films.

Interface morphology of thermal oxide grown on polycrystalline silicon by different processes

1992 ◽  
Vol 50 (2) ◽  
pp. 1396-1397
Author(s):  
H. Yen ◽  
E. P. Kvam ◽  
R. Bashir ◽  
S. Venkatesan ◽  
G. W. Neudeck
Keyword(s):  
Integrated Circuits ◽  
Polycrystalline Silicon ◽  
Silicon Films ◽  
Interface Morphology ◽  
Oxide Interface ◽  
Poly Silicon ◽  
Thermal Oxide ◽  
Grain Orientations ◽  
Polycrystalline Silicon Films ◽  
P Type

Polycrystalline silicon, when highly doped, is commonly used in microelectronics applications such as gates and interconnects. The packing density of integrated circuits can be enhanced by fabricating multilevel polycrystalline silicon films separated by insulating SiO2 layers. It has been found that device performance and electrical properties are strongly affected by the interface morphology between polycrystalline silicon and SiO2. As a thermal oxide layer is grown, the poly silicon is consumed, and there is a volume expansion of the oxide relative to the atomic silicon. Roughness at the poly silicon/thermal oxide interface can be severely deleterious due to stresses induced by the volume change during oxidation. Further, grain orientations and grain boundaries may alter oxidation kinetics, which will also affect roughness, and thus stress.Three groups of polycrystalline silicon films were deposited by LPCVD after growing thermal oxide on p-type wafers. The films were doped with phosphorus or arsenic by three different methods.

Low-Temperature LPCVD MEMS Technologies

2002 ◽  
Vol 729 ◽  
Author(s):  
Roger T. Howe ◽  
Tsu-Jae King
Keyword(s):  
Silicon Germanium ◽  
Polycrystalline Silicon ◽  
Rf Mems ◽  
Sige Layer ◽  
Copper Metallization ◽  
Si Films ◽  
P Type ◽  
Mems Process ◽  
Post Deposition

AbstractThis paper describes recent research on LPCVD processes for the fabrication of high-quality micro-mechanical structures on foundry CMOS wafers. In order to avoid damaging CMOS electronics with either aluminum or copper metallization, the MEMS process temperatures should be limited to a maximum of 450°C. This constraint rules out the conventional polycrystalline silicon (poly-Si) as a candidate structural material for post-CMOS integrated MEMS. Polycrystalline silicon-germanium (poly-SiGe) alloys are attractive for modular integration of MEMS with electronics, because they can be deposited at much lower temperatures than poly-Si films, yet have excellent mechanical properties. In particular, in-situ doped p-type poly-SiGe films deposit rapidly at low temperatures and have adequate conductivity without post-deposition annealing. Poly-Ge can be etched very selectively to Si, SiGe, SiO2 and Si3N4 in a heated hydrogen peroxide solution, and can therefore be used as a sacrificial material to eliminate the need to protect the CMOS electronics during the MEMS-release etch. Low-resistance contact between a structural poly-SiGe layer and an underlying CMOS metal interconnect can be accomplished by deposition of the SiGe onto a typical barrier metal exposed in contact windows. We conclude with directions for further research to develop poly-SiGe technology for integrated inertial, optical, and RF MEMS applications.

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.

Fast Deposition of Polycrystalline Silicon Films by Hot-Wire CVD

1995 ◽  
Vol 377 ◽  
Author(s):  
A. R. Middya ◽  
A. Lloret ◽  
J. Perrin ◽  
J. Huc ◽  
J. L. Moncel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Polycrystalline Silicon ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Hot Wire ◽  
Crystalline Orientation ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTPolycrystalline silicon thin films have been deposited at fast growth rates (50 Å/s) by hotwire chemical vapour deposition (HW-CVD) from SiH4/H2 gas mixtures at low substrate temperature (400–500°C). The surface morphology of these films consists of 0.5 – 2.0μm dendritic grains as seen by electron microscopy. The films have a columnar morphology with grains starting from the substrate either on glass or c-Si. Even the 150 nm thick initial layer is polycrystalline. The preferential crystalline orientation of the poly-Si film is apparently not governed by the radiative source but strongly depends on the type and orientation of the substrate. A strong hydrogen dilution (>90%) of silane is essential to obtain poly-Si films with optimal crystalline structure.

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.

scholarly journals Characterization of Light Emitting Porous Polycrystalline Silicon Films

1996 ◽  
Vol 452 ◽  
Author(s):  
M. C. Poon ◽  
P. G. Han ◽  
J. K. O. Sin ◽  
H. Wong ◽  
P. K. Ko
Keyword(s):  
Photoelectron Spectroscopy ◽  
Polycrystalline Silicon ◽  
Amorphous Materials ◽  
Complex Structure ◽  
Laser Source ◽  
Light Emitting ◽  
Full Wave ◽  
Transmission Electron ◽  
Si Films ◽  
Polycrystalline Silicon Films

AbstractPolycrystalline silicon (poly-Si) thin films (∼700nm) were deposited by LPCVD, doped with 950°C phosphorous diffusion, and rendered porous by anodization and stain etching. From x-ray photoelectron spectroscopy, poly-Si films have atomic concentration of C(ls):0(ls):Si(2p) = 6%:15%:79%. However, porous poly-Si (PPS) films with weak photoluminescence (PL) have C:O:Si of 20%:38%:42%. For PPS films with strong PL, C:O:Si is 11%:38%:51%. From micro-Raman, scattered spectra for 632nm laser source has peak at 735nm and full wave half maximum (FWHM) of 76nm, and is similar to the PL spectra excited by 400nm uv laser source. High resolution transmission electron microscopy (TEM) study shows that PPS film is of complex structure and composes of numerous Si nano-crystals (1∼10nm) surrounded by amorphous materials.

Grain Enhancement of Polycrystalline Silicon Films Aided by Optical Excitation

1997 ◽  
Vol 485 ◽  
Author(s):  
B. L. Sopori ◽  
W. Chen ◽  
J. Alleman ◽  
R. Matson ◽  
N. M. Ravindra ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Low Temperatures ◽  
Polycrystalline Silicon ◽  
Optical Excitation ◽  
Grain Sizes ◽  
Si Solar Cells ◽  
A New Technique ◽  
Si Films ◽  
Polycrystalline Silicon Films

AbstractA new technique for making large-grain thin Si films is described in which optical excitation is used to enhance the grain growth. Grain sizes much larger than the film thickness can be obtained at low temperatures and in short process times. This method is well suited for making thin-film Si solar cells on low-temperature substrates.

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