하부전극 금속 종류에 따른 ALD-Al₂O₃ 박막의 전기적 특성 분석 = Interface characteristics of ALD-Al₂O₃ films using atomic layer deposition with various metal bottom electrodes

다국어 초록 (Multilingual Abstract)

Recently, DRAM technology achieved great success. But, beyond 10mm process, the bottom electrode for the DRAM cell has extremely small features and a high aspect ratio. Conventional MIS(Metal-Insulator-Semiconductor) capacitor of DRAM is considered to be difficult due to insufficient cell capacitance and weak structure. Therefore a lot of people have researched new structure, which is MIM(Metal-Insulator-Metal) capacitor. ALD(Atomic Layer Deposition) method is widely used to semiconductor industry, because ALD process has low process temperature, exact thickness control, high step coverage and good uniformity. MIM capacitor uses TiN or poly-silicon bottom electrode. But it is necessary to develop new electrode materials instead of TiN or poly-silicon.
In this thesis, Al₂O₃ thin film which has a relatively high dielectric constant was deposited by ALD using MPTMA and H₂O on various metals. MIM capacitors were fabricated and analyzed. 2000 A-thick RuO₂, Cu, W, Pt, Al, and TiN were used as a bottom electrode metal. Deposition temperature of Al₂O₃ thin film was 200 ℃ and its thickness was 300 A. As a result of C-V measurement, capacitance of the fabricated MIM capacitor was different for each metal. The largest capacitance was obtained by RuQ₂ and the smallest by TiN. I-V characteristic showed same results with C-V data. TiN bottom electrode had the largest leakage current value and RuO₂ had the smallest value. Probably, it was because metal-insulator interface was different for each metal. This shows that metal-insulator interface is very important factor in case of developing new DRAM's MIM capacitor. Fabricated ALD-Al₂O₃ MIM capacitor's temperature characteristic was good. In the measurement range, capacitance was almost constant. It was found from experimental results that it is possible to fabricate Al₂O₃ MIM capacitor using various metal bottom electrodes prepared by ALD.

목차 (Table of Contents)

• Ⅰ. 서론
• Ⅱ. 실험
• Ⅲ. 결과 및 고찰
• Ⅳ. 결론
• 참고문헌
• Abstract