Temperature Dependence of the Hall Mobility in Polycrystalline Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
S.E. Ready ◽  
J.B. Boyce ◽  
D.K. Fork ◽  
P. Mei ◽  
G.B. Anderson ◽  
...  

Crystallization of amorphous silicon thin films by various methods has fostered enhancements in the electrical characteristics over their amorphous counterparts. For example, carrier mobilities ranging from 10 to >100 cm2/V-sec have been reported for laser crystallized films. The rather large variability of the transport characteristics with crystallization processing conditions is not well understood and, as a result, greatly complicates device process debugging. In addition, while it is generally believed that defects inherent in the grain boundaries provide the primary barriers degrading transport properties relative to single crystal silicon, the specific nature of these defects is not known. In this paper, we present data on the temperature dependence of the Hall mobility of thin silicon films crystallized by thermal and excimer laser processing. Hall data for the laser-crystallized phosphorus-doped material show a temperature dependence which differs dramatically from that for thermally crystallized materials, while the effects of hydrogenation are similar, reducing the barriers at the grain boundaries.

1986 ◽  
Vol 71 ◽  
Author(s):  
T I Kamins

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.


1969 ◽  
Vol 14 (9) ◽  
pp. 255-258 ◽  
Author(s):  
Tadatsugu Itoh ◽  
Taroh Inada ◽  
Masao Ishiki ◽  
Kenshi Menabe

2013 ◽  
Vol 102 (21) ◽  
pp. 212102 ◽  
Author(s):  
T. Antesberger ◽  
T. A. Wassner ◽  
C. Jaeger ◽  
M. Algasinger ◽  
M. Kashani ◽  
...  

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Kuninori Kitahara ◽  
Toshitomo Ishii ◽  
Junki Suzuki ◽  
Takuro Bessyo ◽  
Naoki Watanabe

Raman microscopy was applied to characterize polycrystalline silicon (poly-Si) on glass substrates for application as thin-film transistors (TFTs) integrated on electronic display panels. This study examines the crystallographic defects and stress in poly-Si films grown by industrial techniques: solid phase crystallization and excimer laser crystallization (ELC). To distinguish the effects of defects and stress on the optical-phonon mode of the Si–Si bond, a semiempirical analysis was performed. The analysis was compared with defect images obtained through electron microscopy and atomic force microscopy. It was found that the Raman intensity for the ELC film is remarkably enhanced by the hillocks and ridges located around grain boundaries, which indicates that Raman spectra mainly reflect the situation around grain boundaries. A combination of the hydrogenation of films and the observation of the Si-hydrogen local-vibration mode is useful to support the analysis on the defects. Raman microscopy is also effective for detecting the plasma-induced damage suffered during device processing and characterizing the performance of Si layer in TFTs.


1998 ◽  
Vol 518 ◽  
Author(s):  
H. Kahn ◽  
M.A. Huff ◽  
A.H. Heuer

AbstractSurface-micromachined polysilicon lateral resonant structures were fabricated and used to determine the temperature dependence of the Young's modulus of the polysilicon. This is done by passing a dc current through the beams during resonance testing, resulting in Joule-heating. The temperatures are calibrated by increasing the dc current until the melting point of silicon is attained. The calculated Young's moduli agree well with reported values for single crystal silicon.In addition, metal films were sputter-deposited onto the polysilicon resonators, and similar experiments performed on the composite devices to determine the temperature dependence of the modulus of the sputtered films. Ni films demonstrate a linear decrease in Young's modulus with temperature. TiNi films demonstrate two distinct modulus values with an intermediate transition region, due to the temperature-induced reversible phase transformation exhibited by TiNi.


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