Solid Phase Crystallization of LPCVD Amorphous Si Films by Nucleation Interface Control

1996 ◽  
Vol 448 ◽  
Author(s):  
Eui-Hoon Hwang ◽  
Jae-Sang Ro
Keyword(s):  
Grain Size ◽  
Incubation Time ◽  
Solid Phase ◽  
Composite Films ◽  
Deposition Condition ◽  
Solid Phase Crystallization ◽  
Interface Control ◽  
Amorphous Si ◽  
Si Films ◽  
Deposition Conditions

AbstractA novel method for the fabrication of poly-Si films with a large grain size is reported using solid phase crystallization (SPC) of LPCVD amorphous Si films by nucleation interface control. The reference films used in this study were 1000 Ǻ -thick a-Si films deposited at 500°C at a total pressure of 0.35 Torr using Si2H6/He. Since the deposition condition changes the incubation time, i.e. nucleation rate, and since nucleation occurs dominantly at a-Si/SiO2 interface, we devised the following deposition techniques for the first time in order to obtain the larger gain size. A very thin a-Si layer (~ 50 Ǻ) with the deposition conditions having long incubation time is grown first and then the reference films (~ 950 Ǻ) are grown successively. Various composite films with different combinations were tested. The crystallization kinetics of composite films was observed to be determined by the deposition conditions of a thin a-Si layer at the a-Si/SiO2 interface. Nucleation interface was also observed to be modified by interrupted gas supply resulting in the enhancement of the grain size.

Polycrystalline Si Films Fabricated by Low Temperature Selective Nucleation and Solid Phase Epitaxy Process

1997 ◽  
Vol 485 ◽  
Author(s):  
Claudine M. Chen ◽  
Harry A. Atwater
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Crystal Growth ◽  
Incubation Time ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Grain Sizes ◽  
Random Nucleation ◽  
Nucleation Sites ◽  
Si Films

AbstractWith a selective nucleation and solid phase epitaxy (SNSPE) process, grain sizes of 10 μm have been achieved to date at 620°C in 100 nrm thick silicon films on amorphous SiO2, with potential for greater grain sizes. Selective nucleation occurs via a thin film reaction between a patterned array of 20 rnm thick indium islands which act as heterogeneous nucleation sites on the amorphous silicon starting material. Crystal growth proceeds by lateral solid phase epitaxy from the nucleation sites, during the incubation time for random nucleation. The largest achievable grain size by SNSPE is thus approximately the product of the incubation time and the solid phase epitaxy rate. Electronic dopants, such as B, P, and Al, are found to enhance the solid phase epitaxy rate and affect the nucleation rate.

Grain size, Grain Uniformity, and (111) Texture Enhancement by Solid-phase Crystallization of F- and C-implanted SiGe Films

2000 ◽  
Vol 15 (7) ◽  
pp. 1630-1634 ◽  
Author(s):  
A. Rodríguez ◽  
J. Olivares ◽  
C. González ◽  
J. Sangrador ◽  
T. Rodríguez ◽  
...  
Keyword(s):  
Grain Size ◽  
Vapor Deposition ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solid Phase Crystallization ◽  
Grain Sizes ◽  
Pressure Chemical ◽  
Film Microstructure ◽  
Si Films ◽  
Size Dispersion

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.

Copper-Enhanced Solid Phase Crystallization of Amorphous Silicon Films

1996 ◽  
Vol 424 ◽  
Author(s):  
Dong Kyun Sohn ◽  
Dae Gyu Moon ◽  
Byung Tae Ahn
Keyword(s):  
Solid Phase ◽  
Copper Ions ◽  
Crystallization Time ◽  
Solid Phase Crystallization ◽  
New Process ◽  
Low Temperature Crystallization ◽  
Amorphous Si ◽  
Si Films ◽  
Fractal Size ◽  
Temperature Crystallization

AbstractLow-temperature crystallization of amorphous Si (a-Si) films was investigated by adsorbing copper ions on the surface of the films. The copper ions were adsorbed by spincoating of Cu solution. This new process lowered the crystallization temperature and reduced crystallization time of a-Si films. For 1000 ppm solution, the a-Si film was partly crystallized down to 500°C in 20 h and almost completely crystallized at 530°C in 20 h. The adsorbed Cu on the surface acted as a seed of crystalline and caused fractal growth. The fractal size was varied from 10 to 200 prm, depending on the Cu concentration in solution. But the grain size of the films was about 400 nm, which was similar to that of intrinsic films crystallized at 600°C.

Grain Size Control by Means of Solid Phase Crystallization of Amorphous Silicon

2007 ◽  
Vol 989 ◽  
Author(s):  
Jordi Farjas ◽  
Pere Roura ◽  
Pere Roca i Cabarrocas
Keyword(s):  
Grain Size ◽  
Amorphous Silicon ◽  
Solid Phase ◽  
Size Control ◽  
Substantial Improvement ◽  
Solid Phase Crystallization ◽  
Grain Size Control ◽  
Standard Values ◽  
Standard Set ◽  
Si Films

AbstractThe grain size of thermally crystallized a-Si films is controlled by the nucleation, rN, and growth, rG, rates according to the standard Avrami's theory. Despite this evidence, most papers devoted to improve the crystallized grain size analyze their results with a qualitative reference to this theory. In this paper, we will show that one can identify the standard set of rN and rG values for a-Si and that experiments show that deviations from this standard values always result in a smaller grain size. It is also shown that one cannot expect any substantial improvement with non-conventional heat treatments. Finally, it is argued that a larger grain size is expected from a-Si films containing, in their as-grown state, a controlled density of embedded nanocrystals.

Thin-Film Transistors Fabricated With Poly-Si Films Crystallized by Microwave Annealing

1998 ◽  
Vol 508 ◽  
Author(s):  
YongWoo Choi ◽  
JeongNo Lee ◽  
TaeWoong Jang ◽  
ByungTae Ahn
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Thin Film Transistors ◽  
Solid Phase ◽  
Low Cost ◽  
Solid Phase Crystallization ◽  
Furnace Annealing ◽  
Microwave Annealing ◽  
Si Films ◽  
Better Than

AbstractSolid phase crystallization has the advantages of low cost and excellent uniformity but the crystallization temperature is too high to use glass as a substrate. Using microwave annealing, we crystallized a-Si films at 550 °C within 3 h, which is much shorter than the annealing time at 600 °C of furnace annealing. We fabricated TFTs with poly-Si films crystallized by microwave annealing at low temperature and obtained the characteristics slightly better than or at least comparable to the TFTs by furnace annealing in spite of smaller grain size. This may be due to the improvement of surface roughness of poly-Si film. The poly-Si TFTs with PECVD a-Si film showed better characteristics than the TFTs with LPCVD a-Si film because of larger grain size and smoother Si/SiO2 interface.

Improvement of Grain Size by Crystallization of Double-Layer Amorphous Silicon Films

1994 ◽  
Vol 345 ◽  
Author(s):  
Dae Gyu Moon ◽  
Jeong No Lee ◽  
Ho Bin Im ◽  
Byung Tae Ahn ◽  
Kee Soo Nam ◽  
...  
Keyword(s):  
Grain Size ◽  
Double Layer ◽  
Nucleation Rate ◽  
Incubation Time ◽  
Deposition Temperature ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Double Layers ◽  
Nucleation Sites ◽  
Si Films

AbstractWe investigated the solid phase crystallization (SPC) behavior of 1000 Å amorphous Si (a- Si) films deposited by plasma enhanced chemical vapor deposition (PECVD) at various temperatures and were able to enhance the grain size of the crystallized polysilicon films using double layers of a-Si filns. The deposition temperature of monolayer a-Si films varied from 200 to 400 °C and the films were recrystallized at 600 °C in nitrogen. As the deposition temperature increased, the incubation time was decreased and both the nucleation rate and growth rate were increased. Especially, the nucleation rate strongly depended on the deposition temperature.Since the Si-SiO2 interface provides a large number of nucleation sites, it is desirable to suppress nucleation at the interface. As an idea we employed a structure with double layer a-Si films. The bottom a-Si layer deposited at lower temperature could suppress the nucleation at the Si-SiO2 interface while the top a-Si layer deposited at higher temperature could nucleate with a smaller number of nucleation sites. The incubation time and transformation behavior were determined by the deposition temperature of the top layer. As an example, the grain size of the double layer film deposited sequentially at 150 °C and 200 °C enhanced to 1.8 μm while that of the monolayer film deposited at 200 °C was 1.4 μm.

Solid Phase Epitaxial Regrowth of Microcrystalline Si Films on a (100) Si Substrate

1988 ◽  
Vol 100 ◽  
Author(s):  
S. Roorda ◽  
S. Saito ◽  
W. C. Sinke
Keyword(s):  
Grain Size ◽  
Solid Phase ◽  
Si Substrate ◽  
Two Stage ◽  
Annealing Behaviour ◽  
Explosive Crystallization ◽  
Epitaxial Regrowth ◽  
Amorphous Si ◽  
Si Films ◽  
Size And Structure

ABSTRACTMicrocrystalline Si, as produced by explosive crystallization of an amorphous Si layer on (100) Si, shows a two-stage annealing behaviour. Initially, solid phase epitaxial regrowth occurs very rapidly at temperatures at, or above 800°C. After a few seconds, the regrowth rate slows down to the value typical for alignment of poly-Si. Solid phase epitaxial regrowth of microcrystalline Si is suggested to be strongly dependent on grain size and structure.

Correlation Between Annealing Temperature and Crystallinity of Si Films Prepared by Thermal Plasma Jet Crystallization Technique

2006 ◽  
Vol 910 ◽  
Author(s):  
Hirotaka Kaku ◽  
Seiichiro Higashi ◽  
Tatsuya Okada ◽  
Hideki Murakami ◽  
Seiichi Miyazaki
Keyword(s):  
Phase Transformation ◽  
Thermal Plasma ◽  
Crystalline State ◽  
Annealing Temperature ◽  
Solid Phase ◽  
Plasma Jet ◽  
Solid Phase Crystallization ◽  
Thermal Plasma Jet ◽  
Amorphous Si ◽  
Si Films

AbstractTransient reflectivity of amorphous Si (a-Si) films during thermal plasma jet (TPJ) irradiation has been measured to characterize the phase transformation in millisecond time domain. The a-Si films first transform to crystalline by solid phase crystallization (SPC) followed by melting of the film, and then solidifies to the final crystalline state. By increasing the SPC temperature from about 1100 K to 1300 K, the duration of phase transformation decreases from about 1 ms to 100 μs. The crystallinity of the SPC films is improved not only by annealing the films at a high temperature but also annealing them with longer duration.

The effect of surface nucleation on the evolution of crystalline microstructure during solid phase crystallization of amorphous Si films on SiO2

1997 ◽  
Vol 71 (21) ◽  
pp. 3063-3065 ◽  
Author(s):  
Myung-Kwan Ryu ◽  
Seok-Min Hwang ◽  
Tae-Hoon Kim ◽  
Ki-Bum Kim ◽  
Seok-Hong Min
Keyword(s):  
Solid Phase ◽  
Solid Phase Crystallization ◽  
Surface Nucleation ◽  
Amorphous Si ◽  
Si Films ◽  
Crystalline Microstructure ◽  
Effect Of Surface
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