Fabrication and Characterization of High Temperature Nanostructures

9976577斯奈德几十年来，微电子行业取得了历史上无与伦比的增长。这种增长的引擎是场效应晶体管(FET)，虽然今天的FET与1970年的FET相去甚远，但它仍然是一种FET。现代集成电路中的晶体管被用作电流开关，这与20世纪30年代康拉德·祖斯使用的机电继电器没有什么不同。半导体工业协会(SIA)的路线图呼吁在2010年之前继续依赖FET，但在那之后，道路还不清楚。为了达到更高的集成度，将需要一种方法来避免在非常小的FET中出现的不良影响。该行业的一条可能路径是转向基于纳米结构而不是场效应管的范式。在纳米结构中，器件性能通常随着尺寸的减小而提高。工作温度可能是纳米结构采用的最大障碍。大多数纳米结构只有在接近液氦的温度下才能发挥作用。第二个障碍是需要新的电路体系结构，因为纳米结构制造的晶体管很差。这项提议试图解决这两个障碍。提出了一种新的基于AFM氧化的制备技术，用于制备工作温度在20~77K之间的纳米结构器件。在这一过程中，在AFM的控制下，通过阳极氧化在金属膜上形成图案化，然后与底层硅层反应形成硅化物。硅化物削弱了两侧的氧化线，使氧化线变窄，从而有效地提高了图案的分辨率。这一过程将产生比传统的AFM氧化更窄的隧道势垒的纳米结构。势垒越窄，结电阻越低，器件速度越快。这一新工艺将用于制造量子点细胞自动机(QCA)单元。QCA是一种建立在纳米结构优势基础上的体系结构，使用它们来存储电荷，而不是切换电流。在QCA范式中，信息是由形成细胞的一簇量子点中的电子的位置编码的。QCA单元的状态是通过库仑相互作用由相邻单元的状态决定的，适当的单元排列可以实现任何逻辑功能。以前的实验已经演示了基本的QCA单元、一系列单元和与/或门的操作。应用新的AFM硅化物工艺将有可能展示更大的QCA单元阵列在更高的温度下运行。*

9976577SniderFor decades the microelectronics industry has enjoyed growth that is unparalleled in history. The engine of this growth is the field effect transistor (FET), and while the FET of today is a far cry from that of 1970 it is still an FET. Transistors in modem integrated circuits are used as current switches not unlike the electromechanical relays used by Konrad Zuse in the 1930s. The Semiconductor Industry Association (SIA) roadmap calls for continued dependence on FETs until the year 2010, but after that time the path is unclear. To achieve ever higher integration levels will require an approach that avoids the undesirable effects that appear in very small FETs. One possible path for the industry is a switch to a paradigm based on nanostractures rather than FETs. In nanostructures, the device performance typically improves as the size decreases. Operating temperature is perhaps the greatest obstacle to the adoption of nanostructures. Most nanostructure function only at temperatures near that of liquid helium. A second obstacle is the need for new circuit architecture, since nanostructures make poor transistors.This proposal seeks to address both of these obstacles. A novel fabrication technique based on AFM oxidation is proposed, to produce nanostructure devices with an operating temperature in the range of 20 to 77K. In this process a metal film is patterned by anodic oxidation, controlled by the AFM, and then reacted with the underlying silicon layer to form a silicide. The silicide undercuts the oxide line from each side, narrowing the line and in effect increasing the resolution of the patterning. This process will produce nanostructures with narrower tunnel barriers than are possible using conventional AFM oxidation. Narrower barriers give a lower junction resistance and increased device speed.The new process will be used to fabricate quantum-dot cellular automata (QCA) cells. QCA is an architecture which builds upon the strengths of nanostructures, using them to store charge rather than to switch currents. In the QCA paradigm information is encoded by the positions of electrons in a cluster of quantum dots forming cell. The state of a QCA cell is determined by the state of its neighboring cells through the Coulomb interaction, and proper arrangements of cells can implement any logic function. Previous experiments have demonstrated the operation of a basic QCA cell, a line of cells, and an AND/OR gate. Application of the new AFM silicide process will make it possible to demonstrate larger arrays of QCA cells operating at higher temperatures.***