1. Fabrication of Silicon Nanocones Using RF Microplasma Jet at Atmospheric Pressure 18th SYMPOSIUM ON PLASMA SCIENCE FOR MATERIALS (SPSM-18) ○ Zhongshi Yang  Research Background  Micro-analysis of the Cone Structures  Mechanism of the SNC Growth  Conclusions

2. 背景背景 Synthesis of silicon and carbon nanostructures Research Background field emission devices, UV laser, FET, sensors RF microplasma jet at atmospheric pressure on Fe coated c-Si using a CH 4 -Ar mixture CNTs Nanocones Nanopillars CVD, laser ablation, RIE, electrodeposition

3. c-Si Fe CH 4 Ar Plasma Fabrication Conditions Fabrication Conditions Cathode: WC tube with d of 700 µm Substrate: Fe coated c-Si Fr(Ar):50sccm Fr(CH 4 ) :50 sccm D : 4 mm T s :400ºC RF power:40W

4. The inner diameter of Electrode : 700 µm : 400 ～ ～ 600 μ μ m m : 600 ～ ～ 800 μ μ m m B B C C １００ｎｍ SEM Image １．５ μ ｍ １．５ μ ｍ A : 400μm : 400μm

5. Si O 5μ m Surface Distribution of elements EDX Spectra SEM Image 5μ m C Fe Silicon nanocones (SNCs) Come-shaped products were mainly composed of silicon and SiO 2.

6. TEM 像 SNC A region 60 nm B region CNT SNWs 67nm 20nm 14nm Si 1 1 μ μ m m 1 1 μ μ m m EDX analysis Si nanocrystals are embedded in the cone region

7. Linear Surface Profile CH 4 introduction and Fe film are very important to the SNCs growth. (a) Ar & Ar+CH 4 plasma c-Si etched hole& no cones (a) Ar & Ar+CH 4 plasma c-Si etched hole & no cones (b) Ar plasma Fe/c-Si etched hole& no cones (b) Ar plasma Fe/c-Si etched hole & no cones (c) Ar+CH 4 plasma Fe/c-Si SNCs, SNWs, CNTs plasma substrate results plasma substrate results Fe/c-Si surface

8. ② 照射時間依存 1min 1min 30min 60min 10min ・ Number density increased ・ Average size increased １ μm H R

9. Growth Model of SNCs Ar plasma jet ~20 nm thick Fe layer 1 High gas temperature (2000-3000K) of Ar microplasma jet. 2 Formation of FeSix and FeCx nanoclusters. 3 Catalytic growth by a diffusion of Si and nanocrystalline silicon particles through the FeSix nanoclusters. 4 Silicon oxidation at the outer walls by the plasma heating. CH 4 T g : 2000 ～ 3000K c-Si CH 4 nc-Si particle Si oxidation

10. Si Nanocones (SNCs) were synthesized on Fe-coated c-Si using RF microplasma jet at atmospheric pressure. 18th SYMPOSIUM ON PLASMA SCIENCE FOR MATERIALS (SPSM-18)