指導教授：林克默 博士 報告學生：許博淳 報告日期： 2011/10/24

1. 指導教授：林克默 博士 報告學生：許博淳 報告日期：2011/10/24

2. Results and discussion The crystalline peak at 33°corresponds to the diffraction ofthe (200) plane of the Si substrate.Except for the peak from the Si substrate, there is no prominent peak,which means that the IGZO thin films have an amorphous phase, evenat a relatively high annealing temperature of 600 °C. • Fig. 1. XRD patterns optained from IGZO thin film annealed from 300 to 600 ℃in air for 3hr. The peaks at around 33 °are from the Si substrate. STUT 太陽能材料與模組實驗室

3. Results and discussion Fig. 2. (a and c) High resolution TEM images of IGZO thin films annealed at 300 and 600 °C, respectively. (b and d) Diffraction patterns of IGZO thin films annealed at 300 and 600 °C, respectively. The marked region in (c) indicates a nanocrystal with a size of 5 nm and the inset is a fast Fourier transform (FFT) image of the region with a crystalline phase. STUT 太陽能材料與模組實驗室

4. Results and discussion • As shown in the HRTEM results, the IGZO thin films have a thickness of about 20 nm and an amorphous-like phase. • In the case of the sample annealed at 600 °C, it is observed that a very small amount of crystallization occurs with tiny nanoparticles being formed. • The region designated in Fig. 2(c) shows a nanoparticle with a size of about 5 nm and the fast Fourier transform (FFT) of this region [inset of Fig. 2(c)] confirms that it has a crystalline phase. However, the low density and small size of these crystals result in their producing no diffraction peaks in the XRD measurements and diffraction pattern. STUT 太陽能材料與模組實驗室

5. Results and discussion Fig. 3 shows the opticaltransmittance spectra of the IGZO thin films annealed at 300 and600 °C in a wavelength range of 300–800 nm. These films were spin-coatedon a Corning 1737 glass substrate and show a hightransparency of over 80% in the visible range at annealingtemperaturesof up to 600 °C. Fig. 3. Optical transmittance spectra of thespin coated IGZO thin films on corning 1737glass substrates. STUT 太陽能材料與模組實驗室

6. Results and discussion • Fig. 4. Output characteristics of solution processed IGZO TFTs annealed at (a) 300, (b) 400, (c) 500, and (d) 600 °C. Gate voltage is increased from 0 V to 30 V in a 10 V step. STUT 太陽能材料與模組實驗室

7. Results and discussion • The drain current versus drain to source voltage (ID–VD) output characteristics of the IGZO TFTs depending on the annealing temperature, where the gate voltage is varied from 0 to 30 V. The samples annealed at both 300 and 600 °C exhibit n-type transistor behavior. STUT 太陽能材料與模組實驗室

8. Results and discussion The transfer curves are obtained fromthe drain voltage, showing a saturated drain current in the output curves. The threshold voltage (VTH) can be derived by extrapolating the square root of the drain current versus gate voltage ( ) curve in the saturation region. The TFTs operate in enhancement modewhen the annealing temperature is 400 °C or less. On the other hand, the TFTs annealed at temperatures over 400 °C show depletion mode behavior. Fig. 5. Transfer characteristics for a-IGZO TFTs annealed at different temperatures. STUT 太陽能材料與模組實驗室

9. Conclusion • 使用sol-gel製程並進行熱退火的IGZO薄膜層，能成功製造氧化物薄膜電晶體。 • 退火溫度600℃時IGZO薄膜為非晶相，但還是會觀察到少量的結晶。 • 熱退火後的IGZO薄膜在可見光範圍內的穿透率達80％以上。 • 隨著退火溫度的升高，使載流子濃度變得更高；由於熱退火造成的氧空缺，有助於改變TFT的特性。 STUT 太陽能材料與模組實驗室

10. Thank you for your attention