A Study of the Post-hydrogenation Passivation Mechanism of Crystallized Poly-Si Films

2011 ◽  
Vol 1321 ◽  
Author(s):  
Chong Luo ◽  
Juan Li ◽  
He Li ◽  
Zhiguo Meng ◽  
Chunya Wu ◽  
...  

ABSTRACTThe roles of hydrogen plasma radicals on passivation of several kinds of crystallized poly-Si thin films were investigated using optical emission spectroscopy (OES) combined with Hall mobility, Raman spectra, and absorption coefficient spectra. It was found that different kinds of hydrogen plasma radicals are responsible for passivation of dissimilar poly-Si crystallized by different method. Radicals Hα with lower energy are mainly responsible for passivating the poly-Si crystallized by solid phase crystallization (SPC) whose crystallization precursor was made by plasma enhanced chemical vapor deposition (PECVD). Higher energy radicals H* are more effective in passivating defects left over by Ni in poly-Si crystallized by Metal Induced Crystallization (MIC). The highest energy radicals Hβ and Hγ are needed to passivate the defects in poly-Si crystallized by SPC but whose precursor was made by low pressure CVD (LPCVD).

1996 ◽  
Vol 424 ◽  
Author(s):  
Y.-H. Song ◽  
S.-Y. Kang ◽  
K. I. Cho ◽  
H. J. Yoo ◽  
J. H. Kim ◽  
...  

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.


2000 ◽  
Vol 15 (7) ◽  
pp. 1630-1634 ◽  
Author(s):  
A. Rodríguez ◽  
J. Olivares ◽  
C. González ◽  
J. Sangrador ◽  
T. Rodríguez ◽  
...  

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.


2001 ◽  
Vol 664 ◽  
Author(s):  
Marek A. T. Izmajlowicz ◽  
Neil A. Morrison ◽  
Andrew J. Flewitt ◽  
William I. Milne

ABSTRACTFor application to active matrix liquid crystal displays (AMLCDs), a low temperature (< 600 °C) process for the production of polycrystalline silicon is required to permit the use of inexpensive glass substrates. This would allow the integration of drive electronics onto the display panel. Current low temperature processes include excimer laser annealing, which requires expensive equipment, and solid phase crystallization, which requires high temperatures. It is known that by adding small amounts of metals such as nickel to the amorphous silicon the solid phase crystallization temperature can be significantly reduced. The rate of this solid phase metal induced crystallization is increased in the presence of an electric field. Previous work on field aided crystallization has reported crystal growth that either proceeds towards the positive terminal or is independent of the direction of the electric field. In this work, extensive investigation has consistently revealed directional crystallization, from the positive to the negative terminal, of amorphous silicon thin films during heat treatment in the presence of an electric field. This is the first time that this phenomenon has been reported. Models have been proposed for metal induced crystallization with and without an applied electric field in which a reaction between Ni and Si to produce NiSi is the rate-limiting step. The crystallization rate is increased in the presence of an electric field through the drift of positive Ni ions.


2011 ◽  
Vol 1284 ◽  
Author(s):  
Katherine L. Saenger ◽  
Christian Lavoie ◽  
Roy Carruthers ◽  
Ageeth A. Bol ◽  
Timothy J. Mcardle ◽  
...  

ABSTRACTMetal-catalyzed graphitization from vapor phase sources of carbon is now an established technique for producing few-layer graphene, a candidate material of interest for post-silicon electronics. Here we describe two alternative metal-catalyzed graphene formation processes utilizing solid phase sources of carbon. In the first, carbon is introduced as part of a cosputtered Ni-C alloy; in the second, carbon is introduced as one of the layers in an amorphous carbon (a-C)/Ni bilayer stack. We examine the quality and characteristics of the resulting graphene as a function of starting film thicknesses, Ni-C alloy composition or a-C deposition method (physical or chemical vapor deposition), and annealing conditions. We then discuss some of the competing processes playing a role in graphitic carbon formation and review recent evidence showing that the graphitic carbon in the a-C/Ni system initially forms by a metal-induced crystallization mechanism (analogous to what is seen with Al-induced crystallization of amorphous Si) rather than by the dissolution-upon-heating/precipitation-upon-cooling mechanism seen when graphene is grown by metal-catalyzed chemical vapor deposition methods.


2014 ◽  
Vol 1052 ◽  
pp. 109-114
Author(s):  
Jing Jin ◽  
Xiao Lei Qu ◽  
Wei Min Shi

Solution-based nickel (Ni)-induced crystallization (S-MIC) of amorphous silicon (a-Si) films has been studied with a two-step annealing process. We especially introduced Ethyl cellulose (EC) into the Ni-salt solution, so the viscous Ni-salt solution can be uniformly spin-coated on the a-Si film prepared by plasma enhanced chemical vapor deposition (PECVD). The annealing temperature can be first set from room temperature (RT) to 400°C and kept at 400°C for 2 h in nitrogen ambience. And then, it is increased from 500°C to 550°C and kept for several hours in the following annealing. The correlations among crystallization, the concentrations of Ni-salt solution and annealing conditions can be discussed. The experimental results show that with the help of the two-step annealing, the a-Si films can be crystallized at a low temperature of 500°C. The crystalline fraction gets up to 81.2% after annealing at 520°C for 2 h and the grain size of the polycrystalline Si film is approximately 0.2 μm. Energy dispersive spectroscopy (EDS) analysis shows that very little Ni metal atoms reside in the crystallized Si film for S-MIC.


2007 ◽  
Vol 26-28 ◽  
pp. 623-628 ◽  
Author(s):  
Dong Nyung Lee

Amorphous Si films are generally deposited on glass by physical or chemical vapor deposition. When annealed, they undergo crystallization through nucleation and grain growth. At low annealing temperatures, crystallization starts near the glass substrates for pure Si films and near metals for metal-induced crystallization. In this case, crystallites grow along the <111> directions of c-Si nearly parallel to the film plane, that is, the directed crystallization. The directed crystallization is likely to develop the <110> or <111> orientation, which means the <110> or <111> directions are along the film thickness direction. As the annealing temperature increases, equiaxed crystallization tends to increase, which in turn increases random orientation. When the annealing temperature is further increased, the <111> orientation may be obtained.


Author(s):  
А.О. Замчий ◽  
Е.А. Баранов ◽  
И.Е. Меркулова ◽  
Н.А. Лунев ◽  
В.А. Володин ◽  
...  

A novel fabrication method of polycrystalline silicon by indium-induced crystallization (InIC) of amorphous silicon suboxide thin films with a stoichiometric coefficient of 0.5 (a-SiO0.5) is proposed. It was shown that the use of indium in the annealing process of a SiO0.5 allowed to decrease the crystallization temperature to 600°С which was significantly lower than the solid-phase crystallization temperature of the material - 850°С. As a result of the high-vacuum InIC of a-SiO0.5, the formation of free-standing micron-sized crystalline silicon particles took place.


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