Growth Mechanism of Hydrogen Clusters

1997 ◽  
Vol 467 ◽  
Author(s):  
N. H. Nickel ◽  
G. B. Anderson ◽  
N. M. Johnson ◽  
J. Walker
Keyword(s):  
Fermi Level ◽  
Single Crystal ◽  
Growth Mechanism ◽  
Polycrystalline Silicon ◽  
Single Crystal Silicon ◽  
Surface Region ◽  
Crystal Silicon ◽  
Hydrogen Clusters ◽  
Near Surface ◽  
Crystallographic Planes

ABSTRACTIt is demonstrated that the exposure of polycrystalline silicon (poly-Si) to monatomic hydrogen results in the formation of H clusters. These H stabilized platelets appear in the near-surface region ( 100 nm) and are predominantly oriented along {111} crystallographic planes. Platelet concentrations of ≈5×1015, 1.5×1016-cm−3, and 2.4×1017 cm−3 were observed in nominally undoped poly-Si, phosphorous doped poly-Si (P=1017 cm−3), and phosphorous doped single crystal silicon (P>3×1018 cm−3), respectively. Results obtained on doped c-Si demonstrate that platelet generation occurs only at Fermi-level positions of Ec -EF < 0.4 eV.

Electrical Properties of Polycrystalline-Silicon Thin Films for VLSI

1986 ◽  
Vol 71 ◽  
Author(s):  
T I Kamins
Keyword(s):  
Electrical Properties ◽  
Integrated Circuits ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Crystalline Silicon ◽  
Single Crystal Silicon ◽  
Active Regions ◽  
Crystal Silicon ◽  
Polysilicon Film

AbstractThe electrical properties of polycrystalline silicon differ from those of single-crystal silicon because of the effect of grain boundaries. At low and moderate dopant concentrations, dopant segregation to and carrier trapping at grain boundaries reduces the conductivity of polysilicon markedly compared to that of similarly doped single-crystal silicon. Because the properties of moderately doped polysilicon are limited by grain boundaries, modifying the carrier traps at the grain boundaries by introducing hydrogen to saturate dangling bonds improves the conductivity of polysilicon and allows fabrication of moderate-quality transistors with their active regions in the polycrystalline films. Removing the grain boundaries by melting and recrystallization allows fabrication of high-quality transistors. When polysilicon is used as an interconnecting layer in integrated circuits, its limited conductivity can degrade circuit performance. At high dopant concentrations, the active carrier concentration is limited by the solid solubility of the dopant species in crystalline silicon. The current through oxide grown on polysilicon can be markedly higher than that on oxide of similar thickness grown on singlecrystal silicon because the rough surface of a polysilicon film enhances the local electric field in oxide thermally grown on it. Consequently, the structure must be controlled to obtain reproducible conduction through the oxide. The differences in the behavior of polysilicon and single-crystal silicon and the limited electrical conductivity in polysilicon are having a greater impact on integrated circuits as the feature size decreases and the number of devices on a chip increases in the VLSI era.

Electrical Properties of Epitaxial Silicide-Silicon Interfaces

1985 ◽  
Vol 54 ◽  
Author(s):  
R. T. Tung ◽  
A. F. J. Levi ◽  
J. M. Gibson ◽  
K. K. Ng ◽  
A. Chantre
Keyword(s):  
Fermi Level ◽  
Single Crystal ◽  
Schottky Barrier ◽  
Surface Region ◽  
Ideal Behavior ◽  
Near Surface ◽  
Barrier Heights ◽  
Transmission Electron ◽  
Current Voltage ◽  
P Type

ABSTRACTThe Schottky barrier heights of single crystal NiSi2 layers on Si(111) have been studied by current-voltage, capacitance-voltage and activation energy techniques. Near ideal behavior is found for Schottky barriers grown on substrates cleaned at ∼820°C in ultrahigh vacuum. The Fermi level positions at the interfaces of single crystal type A and type B NiSi2 are shown to differ by ∼0.14 eV. Transmission electron microscopy demonstrated the epitaxial perfection of these suicide layers. At a cleaning temperature of 1050° C, the near surface region of lightly doped n-type Si was converted to p-type. The presence of a p-n junction was directly revealed by spreading resistance measurements and resulted in a high apparent Schottky barrier height (≥0.75 eV) which no longer bears immediate relationship to the interface Fermi level position.

Variations in the Refractive Index of the Near-Surface Region of Low Energy Hydrogen Ion Bombarded Silicon

1985 ◽  
Vol 59 ◽  
Author(s):  
R. B. Pettit ◽  
J. K. G. Panitz
Keyword(s):  
Refractive Index ◽  
Single Crystal Silicon ◽  
Surface Region ◽  
Incident Radiation ◽  
Ion Source ◽  
Index Of Refraction ◽  
Hydrogen Ion ◽  
Crystal Silicon ◽  
Near Surface ◽  
Hydrogen Beam

ABSTRACTUsing ellipsometric analysis, the complex index of refraction of lowenergy, hydrogen ion bombarded, [100] single-crystal silicon was measured as a function of distance from the bombarded surface. The bombardment conditions were a 1600 eV hydrogen beam produced by a Kaufman ion source, 1.4 mA/cm2 flux, 2 × 1018 ions/cm2 fluence and 275°C bulk silicon temperature. These conditions are comparable to the conditions generally reported to result in a substantial increase in the electrical conductivity of polycrystalline silicon solar cell material. The results of this study indicate that the real and imaginary parts of the refractive index of the ion bombarded surface region approach that of the unbombarded substrate at a depth of 50 nm. The refractive index of about the first 10 nm of ion bombarded material is strongly dependent on the bombardment conditions. Variations in the imaginary part of the refractive index indicate that approximately 10% of incident radiation is absorbed by the first 50 nm of modified material.

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