Department of Mechanical Engineering, Stanford University, California 94305, USA.
Langmuir. 2010 May 4;26(9):6845-52. doi: 10.1021/la904122e.
Area-selective atomic layer deposition (ALD) of lead sulfide (PbS) was achieved on octadecyltrichlorosilane (ODTS)-patterned silicon substrates. We investigated the capability of ODTS self-assembled monolayers (SAMs) to deactivate the ALD PbS surface reactions as a function of dipping time in ODTS solution. The reaction mechanism was investigated using density functional theory (DFT), which showed that the initial ALD half-reaction is energetically unfavorable on a methyl-terminated SAM surface. Conventional photolithography was used to create oxide patterns on which ODTS SAMs were selectively grown. Consequently, PbS thin films were grown selectively only where ODTS was not present, whereas deposition was blocked in regions where ODTS was grown. The resulting fabricated patterns were characterized by scanning electron microscopy and Auger electron spectroscopy, which demonstrated that ALD PbS was well confined to defined patterns with high selectivity by ODTS SAMs. In addition, AFM lithography was employed to create nanoscale PbS patterns. Our results show that this method can be applied to various device-fabrication processes, presenting new opportunities for various nanofabrication schemes and manifesting the benefits of self-assembly.
在十八烷基三氯硅烷（ODTS）图案化的硅衬底上实现了硫化铅（PbS）的区域选择性原子层沉积（ALD）。我们研究了 ODTS 自组装单分子层（SAM）作为在 ODTS 溶液中浸泡时间的函数来使 ALD PbS 表面反应失活的能力。使用密度泛函理论（DFT）研究了反应机理，结果表明初始 ALD 半反应在甲基封端的 SAM 表面上能量上是不利的。使用常规光刻在其上选择性生长 ODTS SAM 的方法来创建氧化物图案。结果，仅在不存在 ODTS 的地方生长了 PbS 薄膜，而在生长了 ODTS 的区域中沉积被阻止。通过扫描电子显微镜和俄歇电子能谱对所得图案进行了表征，结果表明，ALD PbS 通过 ODTS SAM 很好地限制在具有高选择性的定义图案中。此外，还采用原子力显微镜光刻技术来创建纳米级 PbS 图案。我们的结果表明，该方法可应用于各种器件制造工艺，为各种纳米制造方案提供了新的机会，并体现了自组装的优势。
