NER: Silicide Quantum Dots for Nanoelectronics

该提案是响应纳米尺度科学与工程倡议，项目招标NSF 01-157，在NER类别。该提案的重点是纳米级硅化物量子点的制造。硅化点在量子元胞自动机和其他量子点器件的制造中具有潜在的用途。量子元胞自动机是量子点的集合，可以完成互连、数字逻辑和存储等基本信息处理功能。探索硅化量子点的一个主要动机是，它们将与硅器件兼容，硅器件可能仍然是纳米电子学与外部世界之间的有用接口。这项研究将探索新的纳米级制造工艺，并将提高对纳米级表面化学反应和相变的理解。我们希望展示原位光刻、金属选择性沉积、硅化物形成和外延层过度生长的集成。特别是，光刻将通过用电子束暴露薄的二氧化硅层来进行，从而增强氧化物从暴露区域的热解吸。随后，量子点将通过化学气相沉积和反应形成金属硅化物。一种特别有吸引力的方法是从有机金属源选择性沉积硅化物形成金属，尽管其他方法也可能被探索。这项研究将使用最近建造的仪器进行，该仪器将电子束图像化与量子点的沉积和表征相结合。所有的工艺步骤，包括量子点的外延过度生长，都可以在不将衬底暴露在大气中的情况下进行。研究中使用的表征工具包括反射高能电子衍射、热解吸质谱和原子力显微镜。在这个为期一年的探索项目中，我们期望在20-40纳米的尺寸范围内制造出图案化的硅化量子点。我们还将获得对选择性生长的更好的科学理解，这将在纳米级器件的制造中广泛有用。

This proposal was received in response to the Nanoscale Science and Engineering Initiative, Program Solicitation NSF 01-157, in the NER category. The proposal focuses on the fabrication of nanoscale silicide quantum dots. Silicide dots are potentially useful for fabrication of quantum cellular automata and other quantum dot devices. Quantum cellular automata are assemblies of quantum dots which can perform the basic information-processing functions of interconnect, digital logic, and memory. A major motivation for the exploration of silicide quantum dots in particular is the fact that they will be compatible with silicon devices which will probably remain useful as an interface between nanoelectronics and the outside world. This research will explore novel nanoscale fabrication processes and will develop improved understanding of surface chemical reactions and phase transitions on the nanoscale. We wish to demonstrate the integration of in situ lithography, selective deposition of metals, silicide formation, and epitaxial layer overgrowth. In particular, lithography will be performed by exposing thin silicon dioxide layers with an electron beam, thereby enhancing thermal desorption of oxide from the exposed regions. Subsequently the quantum dots will be formed by chemical vapor deposition and reaction to form a metallic silicide. One particularly attractive approach is selective deposition of the silicide-forming metal from an organometallic source, although other approaches may also be explored. This research will be performed using a recently constructed apparatus which combines electron beam patterning with the deposition and characterization of quantum dots. All process steps, including epitaxial overgrowth of the quantum dots, can be performed without exposing the substrates to atmosphere. Characterization tools to be used in the work include reflection high energy electron diffraction, thermal desorption mass spectrometry, and atomic force microscopy. Within this one-year exploratory program, we expect to fabricate patterned silicide quantum dots in the 20-40 nm size range. We will also obtain improved scientific understanding of selective growth which will be broadly useful in the fabrication of nanoscale devices.