Excimer Laser Recrystallization of Selectively Floating a-Si Active Layer for Large-Grained Poly-Si Film

2001 ◽  
Vol 664 ◽  
Author(s):  
Cheon-Hong Kim ◽  
Juhn-Suk Yoo ◽  
In-Hyuk Song ◽  
Min-Koo Han
Keyword(s):  
Excimer Laser ◽  
Active Layer ◽  
Laser Annealing ◽  
Layer Structure ◽  
Excimer Laser Annealing ◽  
Lateral Direction ◽  
Thermal Insulating ◽  
Laser Recrystallization ◽  
Lateral Temperature ◽  
Annealing Method

ABSTRACTWe report a new excimer laser annealing method by employing selectively floating a-Si active layer structure in order to increase the grain size of poly-Si film. The floating a-Si region blocks the heat conduction into the underlying substrate due to high thermal-insulating property of an air so that the lateral temperature gradient is successfully induced by the proposed simple air-gap structure. Our experimental results show that large grains were grown in the lateral direction from the edge to the center of the floating active region. The large grains exceeding 4 m were successfully obtained with only one laser irradiation.

Artificial Formation of Nucleation Seed in Excimer Laser Recrystallization Of Poly-Si

1999 ◽  
Vol 558 ◽  
Author(s):  
Jae-Hong Jeon ◽  
Kee-Chan Park ◽  
Ji-Hoon Kang ◽  
Min-Cheol Lee ◽  
Min-Koo Han
Keyword(s):  
Excimer Laser ◽  
Polycrystalline Silicon ◽  
Laser Annealing ◽  
Thin Film Transistor ◽  
Excimer Laser Annealing ◽  
Laser Recrystallization ◽  
Conventional Laser ◽  
Annealing Method ◽  
Si Thin Film

ABSTARCTExcimer laser annealing method employing artificial nucleation seed is proposed to increase the grain size of polycrystalline silicon(poly-Si). We utilize Si component incorporated in aluminum(Al)-sputtering source for the nucleation seed. Si clusters which are to be used as nucleation seed are successfully formed on the substrate by deposition and etch-back of Si-incorporated Al layer. Irradiation of excimer laser on amorphous silicon(a-Si) film deposited on the substrate prepared by our method results in enlargement of poly-Si grains, compared with conventional laser recrystallization. Poly-Si thin film transistor also shows much improved electrical perfbrmance which directly reflects the quality of poly-Si film recrystallized by our method.

Enhancement of On/Off Current Ratio of Poly-Silicon TFT by Selective Laser-Induced Crystallization of Active Layer

1997 ◽  
Vol 471 ◽  
Author(s):  
Jae-Hong Jeon ◽  
Cheol-Min Park ◽  
Hong-Seok Choi ◽  
Cheon-Hong Kim ◽  
Min-Koo Han
Keyword(s):  
Leakage Current ◽  
Excimer Laser ◽  
Active Layer ◽  
Laser Annealing ◽  
Wave Length ◽  
Excimer Laser Annealing ◽  
Current Ratio ◽  
Ito Film ◽  
Conduction Channel ◽  
Induced Crystallization

ABSTRACTWe have proposed the new poly-Si TFT which reduces the leakage current effectively by employing highly resistive a-Si region in the channel. The active layer of proposed device is crystallized selectively by employing excimer laser annealing while the both sides of channel near the source/drain are not recrystallized and remained as a-Si. Unlikely LDD or offset structure, the a-Si region which is designed to reduce the leakage current acts as the conduction channel of carriers under the ON state, so that the ON current is decreased very little. The selectively crystallized active layer can be fabricated by irradiating the excimer laser through ITO film of which transmittance at the wave length of laser is selectively adjusted. In the course of fabricating the proposed device, any additional photo masking step is not necessary and misalign problem is eliminated. The experimental results show that the ON/OFF current ratio of proposed poly-Si TFT is 106 while that of conventional one is 105.

Ultra-Low Temperature Poly-Si Thin Film by Excimer Laser Recrystallization For Flexible Substrates

2003 ◽  
Vol 769 ◽  
Author(s):  
Sang-Myeon Han ◽  
Min-Cheol Lee ◽  
Su-Hyuk Kang ◽  
Moon-Young Shin ◽  
Min-Koo Han
Keyword(s):  
Low Temperature ◽  
Excimer Laser ◽  
Inductively Coupled Plasma ◽  
Laser Annealing ◽  
Silicon Film ◽  
Chemical Vapor ◽  
Plastic Substrate ◽  
Excimer Laser Annealing ◽  
Plasma Chemical Vapor Deposition ◽  
Laser Recrystallization

AbstractAn ultra-low temperature (< 200°C) polycrystalline silicon (poly-Si) film is fabricated for the plastic substrate application using inductively coupled plasma chemical vapor deposition (ICP-CVD) and excimer laser annealing. The precursor active layer is deposited using the SiH4/He mixture at 150°C (substrate). The deposited silicon film consists of crystalline component as well as hydrogenated amorphous component. The hydrogen content in the precursor layer is less than 5 at%. The grain size of the precursor active silicon film is about 200nm and it is increased up to 500nm after excimer laser irradiation.

Lateral Grain Growth in the Excimer Laser Crystallization of Poly-Si

1994 ◽  
Vol 321 ◽  
Author(s):  
H. Kuriyama ◽  
K. Sano ◽  
S. Ishida ◽  
T. Nohda ◽  
Y. Aya ◽  
...  
Keyword(s):  
Grain Size ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Field Effect Mobility ◽  
Laser Crystallization ◽  
Excimer Laser Annealing ◽  
Short Processing Time ◽  
Low Temperature Processing ◽  
Excimer Laser Crystallization ◽  
Annealing Method

ABSTRACTWe have succeeded in obtaining nondoped, thin poly-Si film (thickness ∼500Å) with excellent crystallinity and large grain size (Maximum grain size ∼4.5 μ m) by an excimer laser annealing Method, which offers the features of low-temperature processing and a short processing time. The grain size distribution shrinks in the region around 1.5 μ m and this poly-Si film exhibits a strong (111) crystallographic orientation. Poly-Si thin film transistors using these films show quite a high field effect mobility of 440cm2/V · s below 600°C process.

Experimental Analysis for Low-Temperature Poly-Si Films Produced by Using the Excimer Laser Annealing Method

2006 ◽  
Vol 505-507 ◽  
pp. 277-282 ◽  
Author(s):  
Yu Ru Chen ◽  
Long Sun Chao
Keyword(s):  
Grain Size ◽  
Excimer Laser ◽  
Glass Substrate ◽  
Laser Annealing ◽  
Pulse Number ◽  
Sio2 Layer ◽  
Excimer Laser Annealing ◽  
Melt Pool ◽  
Si Films ◽  
Annealing Method

This paper is to investigate the effects on grain size of different working conditions for making poly Si films by using the excimer laser annealing method. In this research, a KrF excimer laser of 248 nm in wavelength is used to irradiate a-Si films of 0.1 μm in thickness on glass substrate to produce poly-Si ones. The control parameters are laser intensity (200~500 mJ/cm2), pulse number (1~10 shots) and coverage fraction (0~100%). Besides, the effect of a SiO2 layer is also studied, which is utilized as a heat-isolated zone located between the Si film and glass substrate. Average grain sizes from SEM photos are used to analyze the effects of these parameters. Purely from the heat transfer view, the Si film obtains more energy would have the slower cooling or solidification rate, which results in the larger grain. From the experimental results, if the melt pool is within the range of Si film or does not contact its neighboring layer (SiO2 layer or glass substrate), the more absorbed energy from the higher energy intensity, the larger pulse number or the bigger coverage fraction can have the larger average grain size. However, with large enough energy, the melt pool could go through the Si film and touch the lower layer. This would induce much more nuclei due to the homogeneous nucleation in the pool and the heterogeneous nucleation near the interface between the film and the neighboring layer. The resulting grain size is much smaller than that of the former one. The transition points of these two cases for different control parameters can be obtained from the experimental results in this study. When the energy from the laser is small, the SiO2 layer acts like a heat absorber and makes the grain size smaller than that of not having the SiO2 layer. On the other hand, when the energy is large, the SiO2 layer becomes a heat insulator and makes the grain size larger.

Lateral Grain Growth of Poly-Si Films with a Specific Orientation by an Excimer Laser Annealing Method

1993 ◽  
Vol 32 (Part 1, No. 12B) ◽  
pp. 6190-6195 ◽  
Author(s):  
Hiroyuki Kuriyama ◽  
Tomoyuki Nohda ◽  
Satoshi Ishida ◽  
Takashi Kuwahara ◽  
Shigeru Noguchi ◽  
...  
Keyword(s):  
Grain Growth ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Excimer Laser Annealing ◽  
Si Films ◽  
Specific Orientation ◽  
Annealing Method

Improving the Uniformity of Poly-Si Films Using a New Excimer Laser Annealing Method for Giant-Microelectronics

1992 ◽  
Vol 31 (Part 1, No. 12B) ◽  
pp. 4550-4554 ◽  
Author(s):  
Hiroyuki Kuriyama ◽  
Takashi Kuwahara ◽  
Satoshi Ishida ◽  
Tomoyuki Nohda ◽  
Keiichi Sano ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Laser Annealing ◽  
Excimer Laser Annealing ◽  
Si Films ◽  
Annealing Method

Poly-Si Thin Film Transistors Fabricated By Employing Selective Si Ion-Implantation And Excimer Laser Annealing

2000 ◽  
Vol 609 ◽  
Author(s):  
Min-Cheol Lee ◽  
Jae-Hong Jeon ◽  
Jin-Woo Park ◽  
Min-Koo Han
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Defect Density ◽  
Mask Pattern ◽  
Excimer Laser Annealing ◽  
Boundary Location ◽  
Si Ion Implantation ◽  
Annealing Method

ABSTRACTA new excimer laser annealing method is proposed in order to produce the poly-Si film with low defect density and large grain, by combining the selective Si ionimplantation and excimer laser annealing. Selective Si ion-implantation is employed to form artificial nucleation seeds in a-Si film prior to excimer laser annealing in order to increase the nucleation probability. The grain boundary location in poly-Si film has been controlled through implantation mask, and the grain size around micrometer order is obtained without any other process. TEM result shows that grain boundary is controlled according to mask pattern and the crystallinity of the poly-Si film is improved.

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