1 nano-aluminum-induced crystallization of amorphous silicon 指導教授:管 鴻 學...
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Nano-aluminum-induced crystallization Nano-aluminum-induced crystallization of amorphous siliconof amorphous silicon
指導教授:管 鴻指導教授:管 鴻學 生:郭豐榮學 生:郭豐榮學 號:學 號:M98L0213M98L0213
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OutlineOutline
• INTRODUCTION
• EXPERIMENTAL
• RESULTS AND DISCUSSION
• CONCLUSION
• REFERENCES
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INTRODUCTIONINTRODUCTION
• Increasing the average crystallite size of the poly-crystalline silicon is one very important aspect of research on AIC of a-Si:H
• Compared to traditional AIC, the nano-AIC method produces much smoother polycrystalline silicon films with significantly larger crystallites whose size increases with annealing temperature ramp-up time
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EXPERIMENTALEXPERIMENTAL
☼ PECVD
☼ a-Si:H : 100 nm
☼ RF power : 15 W
☼ pressure : 0.5 Torr
☼ Ts : 250 ℃
☼ SiH4 : 85 sccm
☼ Thermal evaporation
☼ Al : 30 nm
☼ Al : 200 nm
☼ Annealing
☼ At 350 in N℃ 2
☼ Time : 30 min
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RESULTS AND DISCUSSIONRESULTS AND DISCUSSION
Fig. 1. Microscopy and SEM images of the polycrystalline silicon film created by (a) nano-AIC of a-Si:H and (b) traditional AIC, respectively. The image inserted in (b) is a SEM photo showing details of small grains.
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RESULTS AND DISCUSSIONRESULTS AND DISCUSSION
Fig. 2. Relations between grain size and ramp up time of annealing temperature.It shows that grain size significantly increased with ramp up time for nano-AIC of a-Si:H, but changed little for traditional AIC of a-Si:H
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RESULTS AND DISCUSSIONRESULTS AND DISCUSSION
Fig. 3. Microscopy images of the grains on the samples with 20 h annealing ramp time. The largest grain size is about 90 μm, the largest size has not been reported in literature.
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RESULTS AND DISCUSSIONRESULTS AND DISCUSSION
Fig. 4. 3-D SPM images showing the surface topography of (a) a-Si:H, and polycrystalline silicon films produced by (b) nano-AIC, and (c) traditional AIC. It shows that nano-AIC created much smoother surfaces than traditional AIC.
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RESULTS AND DISCUSSIONRESULTS AND DISCUSSION
Fig. 5. XRD spectra of (a) a-Si:H, (b) nano-AIC of a-Si:H, and (c) traditionalAIC of a-Si:H. The large peaks around 2θ=28.5° are Si (111), indicatingcrystallization occurred for both (b) and (c).
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CONCLUSIONCONCLUSION
• For any given ramp-up time, the grains created by nano-AIC of a-Si:H are much larger than those produced by traditional AIC of a-Si:H
• This paper reports on the successful fabrication of continuous and smooth polycrystalline silicon films with very large grains using AIC of a-Si:H
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REFERENCESREFERENCES• Min Zou a,*, Li Cai b, Hengyu Wang a, William Brown b , a Department of
Mechanical Engineering, The University of Arkansas, Fayetteville, AR 72701, USA. b Department of Electrical Engineering, The University of Arkansas, Fayetteville, AR 72701, USA. Received 14 June 2005; accepted 10 November 2005 .Available online 9 December 2005.