Exploring the Limits of Scaling and 3D-integration for Edge-contacted Nanomaterial-based Transistors

探索基于边缘接触纳米材料的晶体管的缩放和 3D 集成的极限

• 批准号: 2227175
• 负责人: Aaron Franklin
• 金额: $ 39.87万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2227175&HistoricalAwards=false
• 关键词: Exploring; Limits; Scaling; 3D; integration

Nontechnical:This NSF project aims to address longstanding questions related to the electrical interface between semiconducting nanomaterials and conducting metals. Nanomaterials show great promise for enabling a continuation of Moore’s law, which relates to the increase in computational capability using integrated circuits. By using nanomaterials for the semiconductor in transistors, these core computing devices can be scaled to smaller dimensions with increased performance compared to traditional semiconductors, such as silicon. Yet, there remain many questions about how electrical current flow is controlled between nanomaterials and contact metals. This project will bring transformative change to the field by using custom-designed device structures to study the behavior and control of electrical current at various metal-nanomaterial interfaces. Using what is known as an edge-contact geometry, both n-type and p-type nanomaterial-based transistors will be studied and ultimately demonstrated in a 3D integrated circuit. The intellectual merits of the project include addressing scientific questions related to how current is controlled at metal-nanomaterial interfaces at scaled dimensions. The new insights generated from these studies will advance the field of nanoelectronics through increased understanding of the scaling limits and evidence for a new approach to achieving 3D integration of devices. The broader impacts of the project include the advancement of devices for future integrated circuits and the engagement of students underrepresented in engineering. The advancements in this project can enable new integrated circuit designs for transistors to lower power consumption in energy-hungry applications such as data centers. Through this project, two graduate students from groups underrepresented in engineering will be supported, along with several new outreach initiatives to involve K-12 and undergraduates in the research effort. Technical:Nanomaterials offer many advantages for use in future transistor technologies. Yet, there remain scientific unknowns and obstacles to the fabrication and integration of nanomaterial-based transistors. This project seeks to address several longstanding questions related to metal-nanomaterial contact interfaces for 2D transition metal dichalcogenides (TMDs) and 1D carbon nanotubes (CNTs). Four distinct goals will be pursued, each relating to a specific aspect of metal-nanomaterial contacts. The first goal will be to address the question of whether contact gating in 2D transistors influences the contact length scaling behavior. Virtually all devices to date have included bottom-gate structures with the gate overlapping the source/drain contacts. This produces a gating effect on the semiconductor beneath the metal contacts and the influence of this effect has been hypothesized but never experimentally studied – such a study will be pursued with a large set of Molybdenum disulfide (MoS2) devices designed for characterization with and without an overlapping gate. The second goal will be to determine the impact of ambient air exposure during the fabrication of 1D edge contacts to 2D TMDs. Edge contacts are the most scalable because they only interface with the nanomaterial abruptly at the edge of the metal; however, there are very few reports of these contact structures and these contain conflicting claims regarding the influence of air exposure prior to metal contact deposition. A systematic and parametric study will be performed on four distinct edge-contact formation processes using 2D MoS2 and Tungsten diselenide (WSe2). The third goal will be to develop the first low-temperature (400 C) edge-contact formation process for CNTs, which offer p-type devices that couple well with n-type MoS2 devices. Finally, the fourth goal will be to integrate the edge-contacted n-type MoS2 transistors with the edge-contacted p-type CNT transistors to demonstrate vertical monolithic integration that is back-end-of-line (BEOL) compatible; what’s more this demonstrated approach also cuts one masking layer out of the process by having the edge contacts formed in the same step as the contact vias. Overall, the results of pursuing these goals will be key scientific insights into metal-nanomaterial contacts applicable to a broad range of device applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术性：这个NSF项目旨在解决与半导体纳米材料和传导金属之间的电界面有关的长期问题。纳米材料对实现摩尔定律的延续表现出了巨大的希望，这与使用集成电路的计算能力提高有关。通过将纳米材料用于晶体管中的半导体，与传统的半导体（例如硅）相比，这些核心计算设备可以缩放到较小的尺寸，性能提高。然而，关于纳米材料和接触金属之间如何控制电流流程的问题，还有很多问题。该项目将通过使用定制设计的设备结构来研究各种金属纳米材料接口处的电流的行为和控制，从而为现场带来变革性的变化。使用所谓的边缘接触几何形状，N型和P型基于纳米材料的晶体管都将进行研究，并最终在3D集成电路中证明。该项目的智力优点包括解决与缩放尺寸的金属纳米材料界面处的当前如何控制的科学问题。这些研究产生的新见解将通过对缩放限制的理解和证据来实现3D整合设备的新方法，从而推动纳米电子学领域。该项目的更广泛的影响包括为未来综合电路的设备发展，以及在工程学中代表不足的学生的参与度。该项目的进步可以使晶体管的新综合电路设计能够降低渴望能源的应用程序（例如数据中心）的功耗。通过该项目，将支持来自工程领域人数不足的两名研究生，以及一些新的外展计划，以涉及K-12和本科生参与研究工作。技术：纳米材料为将来的晶体管技术提供了许多优势。然而，仍然存在科学的未知数和基于纳米材料的晶体管的制造和整合的障碍。该项目旨在解决与金属纳米材料接触界面有关的几个长期问题，用于2D过渡金属二甲构基化金（TMDS）和1D碳纳米管（CNTS）。将实现四个不同的目标，每个目标都与金属纳米材料接触的特定方面有关。第一个目标是解决2D晶体管中的接触门控是否影响接触长度缩放行为的问题。迄今为止，几乎所有设备都包含底闸结构，而门与源/排水接触重叠。这会对金属接触下的半导体产生门控效应，并且已经假设了这种效果的影响，但从未实验研究 - 将使用大量二硫化钼（MOS2）设备进行此类研究，设计用于具有和没有重叠门的表征。第二个目标是确定在制造1D边触点对2D TMD的制造过程中环境空气暴露的影响。边缘触点是最可扩展的，因为它们仅在金属边缘突然与纳米材料接口。但是，这些接触结构的报道很少，这些报告包含有关金属接触沉积之前空气暴露的影响的矛盾主张。使用2D MOS2和Dungsten diselenide（WSE2），将对四个不同的边缘接触过程进行系统和参数研究。第三个目标是开发CNTS的第一个低温（400 C）边缘接触过程，该过程提供了与N型MOS2设备配对的P型设备。最后，第四个目标是将边缘连接的N型MOS2晶体管与边缘触发的P型CNT晶体管集成，以展示垂直整体式整合，该整体式集成是后端（BEOL）兼容；更重要的是，这种证明的方法还通过与触点VIA相同的步骤形成边缘触点，从而使一个掩蔽层脱离了过程。总体而言，追求这些目标的结果将是对适用于广泛设备应用的金属纳米材料接触的关键科学见解。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛影响的审查标准通过评估来获得支持的。