Atomic Layer Deposition of HfO2 Thin Films Exploiting Novel Cyclopentadienyl Precursors at High Temperatures
详细信息 查看全文
- 作者：Jaakko Niinistö ; Matti Putkonen ; Lauri Niinistö ; Fuquan Song ; Paul Williams ; Peter N. Heys ; Rajesh Odedra
- 刊名：Chemistry of Materials
- 出版年：2007
- 出版时间：June 26, 2007
- 年：2007
- 卷：19
- 期：13
- 页码：3319 - 3324
- 全文大小：297K
- 年卷期：v.19,no.13(June 26, 2007)
- ISSN：1520-5002
文摘
Atomic layer deposition (ALD) of HfO2 thin films was studied using four novel cyclopentadienylprecursors, namely, (CpMe)2HfMe2, Cp2Hf(OMe)2, (CpMe)2Hf(OMe)Me, and (CpMe)2Hf(OMe)2. Ozonewas used as the oxygen source. Among the cyclopentadienyl precursors, (CpMe)2HfMe2 and (CpMe)2Hf(OMe)Me were the most promising, showing ALD-type growth characteristics at high temperaturesas the self-limiting growth mode was confirmed at 400 
C. ALD-type growth was verified also on 60:1aspect ratio trench structures even at 450 C, where perfect conformality was obtained. The growth ratestayed nearly constant at around 0.5 Å/cycle at substrate temperatures between 350 and 500 C. WhenCp2Hf(OMe)2 and (CpMe)2Hf(OMe)2 were applied, slight decomposition of the precursor was detectedat 350-400 C, and thus a self-limiting growth mode was not achieved. Time-of-flight elastic recoildetection analyses demonstrated stoichiometric HfO2 films, where impurity concentrations were below0.1 at % for C, H, and N in films deposited from each of the four Hf precursors. In addition, thin HfO2films showed good dielectric properties such as low hysteresis, nearly ideal flatband voltage, and effectivepermittivity values similar to previously reported HfO2 films obtained by the alkylamide-based processes.
C. ALD-type growth was verified also on 60:1aspect ratio trench structures even at 450 C, where perfect conformality was obtained. The growth ratestayed nearly constant at around 0.5 Å/cycle at substrate temperatures between 350 and 500 C. WhenCp2Hf(OMe)2 and (CpMe)2Hf(OMe)2 were applied, slight decomposition of the precursor was detectedat 350-400 C, and thus a self-limiting growth mode was not achieved. Time-of-flight elastic recoildetection analyses demonstrated stoichiometric HfO2 films, where impurity concentrations were below0.1 at % for C, H, and N in films deposited from each of the four Hf precursors. In addition, thin HfO2films showed good dielectric properties such as low hysteresis, nearly ideal flatband voltage, and effectivepermittivity values similar to previously reported HfO2 films obtained by the alkylamide-based processes.