Three-Dimensional Magnetic Memory Device

三维磁存储器件

• 批准号: 0501297
• 负责人: Armando Barreto
• 金额: --
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0501297&HistoricalAwards=false
• 关键词: Three; Dimensional; Magnetic; Memory; Device

Intellectual Merit The objective of this proposal is to explore 3-D magnetic recording in order to produce future high-performance memory devices. There is increasing demand for data and this demand will continue to exponentially grow. However, this year for the first time, researchers witnessed that the recorded data in conventional longitudinal magnetic media becomes highly unstable as the areal density increases beyond approximately 100 Gbit/in2. Most of these known alternative technologies are of 2-D nature and promise to defer the superparamagnetic limit beyond one terabit/in2. However, to defer the superparamagnetic limit substantially beyond the one terabit/in2 mark, it will be necessary to stack recording layers in the third (vertical) dimension. The vertical stacking underlies the concept of 3-D magnetic memory - the primary subject of this proposal. Several implementations of a 3-D memory device are proposed. The physics underlying the alternative implementations will be comparatively studied from both theoretical and experimental perspectives. Through these experiments, it is proposed to use focused ion beam (FIB) to fabricate test structures with sub-100-nm dimensions. The focus will be on the study of three components: 1) medium, 2) write and 3) read processes. One of the proposed mechanisms to access data takes advantage of an earlier developed (for perpendicular recording) method to control strong magnetic fields using a "soft" magnetic underlayer (SUL) under the 3-D recording medium. During the write process, the use of the SUL allows to considerably increase the recording field across the entire thickness of the 3-D medium. During the readback process, the "softness" of the SUL strongly influences the sensitivity field (for the Reciprocity Principle) and thus will be used as a mechanism to identify a uni-field plane (2-D layer). To minimize the inter-symbol interference and improve stability, it is proposed to pattern the recording medium in all three dimensions. The physics of 3-D magnetic recording will be also investigated theoretically with Landau-Lifshits-Gilbert-based micromagnetic modeling and Monte-Carlo-based temperature simulations. Magnetic force microscopy (MFM) and optical Kerr Microscopy will be used to study the intergranular interactions in the recording medium. Finally, to learn how to efficiently analyze and read back information from the bulk of the 3-D medium, it is proposed to take advantage of a signal processing technique such as "constrained deconvolution". Basic Co/Pt-based 3-D medium thin-films necessary for this study will be fabricated inhouse using co-sputter deposition. With optical lithography and following FIB trimming, nanoscale bit cells will be tested. To conduct a comparative study of 3-D magnetic recording, Seagate Technology commits to provide additional recording transducers (for further FIB trimming at FIU) and various forms of recording media (patterned via E-beam-based lithography), and help with additional characterization methods. In addition, to support this work, Seagate has offered to donate a 13-chamber sputtering system by Balzers Corporation. The ultimate goal of this project is to develop guidelines to design an adequate 3-D medium and understand the physics of write and read processes.Broader Impacts This project is interdisciplinary in nature. Its success depends on the adequate integration of the engineering experience in data storage with the understanding of the basic physics of magnetic recording devices and knowledge of advanced data recognition methods. Based at one of the largest minority-serving and one of the youngest research institutions (FIU), this joint project with strong industrial ties promises to boost the research initiatives at FIU and strongly promote the involvement of underrepresented groups in advanced research. Throughout these research efforts, PIs have established a tradition of inviting leading researchers to offer colloquia at FIU. The interest in research on Nanoscale information systems at FIU has significantly grown due current joint efforts. In one year alone, the number of students (mostly minority) involved in the study of nanoscale magnetic devices has grown from one to twelve. As for the technological impact, due to the nature of this project, it will contribute to the advancement of the multi-billion-dollar data storage industry. From a short-term perspective, similar to popular flash memory today, 3-D magnetic memory could be used as a USB-compatible device with significantly higher data capacity. In the long-term perspective, 3-D magnetic memory may replace conventional magnetic hard-drives and other memory technologies, and under the right circumstances may even transform into single-chip computing. Finally, 3-D memory goes well along the expected general future trend of vertical integration.

该提案的目的是探索3-D磁记录，以生产未来的高性能存储设备。对数据的需求越来越大，而且这种需求将继续呈指数级增长。然而，今年研究人员首次发现，当面密度超过约100 Gbit/in2时，传统纵向磁介质中记录的数据变得非常不稳定。大多数这些已知的替代技术是2-D的性质，并承诺推迟超顺磁极限超过1太比特/平方英寸。然而，为了使超顺磁极限基本上延迟超过1太比特/英寸2标记，将需要在第三（垂直）维度上堆叠记录层。垂直堆叠是三维磁记忆概念的基础--这一提议的主要主题。提出了3-D存储器设备的若干实现。替代实现的物理基础将从理论和实验的角度进行比较研究。通过这些实验，提出了使用聚焦离子束（FIB）制作亚100纳米尺寸的测试结构。重点将放在三个组成部分的研究：1）媒体，2）写和3）读过程。所提出的访问数据的机制之一利用了早期开发的（用于垂直记录）方法，以使用3-D记录介质下的"软"磁底层（SUL）来控制强磁场。在写入过程期间，SUL的使用允许显著增加跨越3-D介质的整个厚度的记录场。在回读过程中，SUL的“柔软度”强烈影响灵敏度场（对于互易原理），因此将被用作识别单场平面（2-D层）的机制。为了最小化符号间干扰并提高稳定性，提出了在所有三个维度上图案化记录介质。三维磁记录的物理学也将在理论上研究与朗道-Lifshits-吉尔伯特为基础的微磁建模和蒙特-卡罗为基础的温度模拟。磁力显微镜（MFM）和光学克尔显微镜将用于研究记录介质中的颗粒间相互作用。最后，为了学习如何有效地分析和读回信息从大部分的3-D介质，它被建议利用信号处理技术，如“约束反卷积”。本研究所需的基本Co/Pt基3-D介质薄膜将使用共溅射沉积在内部制造。利用光刻和随后的FIB修整，将测试纳米级位单元。为了进行3D磁记录的比较研究，Seagate Technology承诺提供额外的记录传感器（用于在FIU进行进一步的FIB微调）和各种形式的记录介质（通过基于电子束的光刻形成图案），并帮助提供额外的表征方法。此外，为了支持这项工作，Seagate已提出捐赠巴尔泽公司的13室溅射系统。该项目的最终目标是制定指导方针，以设计适当的3-D介质，并了解写入和读取过程的物理学。更广泛的影响该项目是跨学科的性质。它的成功取决于数据存储的工程经验与磁记录设备的基本物理知识和先进的数据识别方法的知识的充分整合。基于最大的少数民族服务和最年轻的研究机构之一（金融情报室），这个具有强大的行业联系的联合项目有望推动金融情报室的研究举措，并大力促进代表性不足的群体参与先进的研究。在这些研究工作中，PI建立了邀请主要研究人员在金融情报室举行座谈会的传统。由于目前的共同努力，金融情报所对纳米级信息系统研究的兴趣大大增加。仅在一年内，参与纳米磁性器件研究的学生（大多数是少数民族）就从1人增加到12人。 至于技术影响，由于该项目的性质，它将有助于推动价值数十亿美元的数据存储行业的发展。从短期的角度来看，类似于今天流行的闪存，3D磁性存储器可以用作USB兼容设备，具有更高的数据容量。从长远来看，3D磁性存储器可能会取代传统的磁性硬盘和其他存储器技术，在适当的情况下甚至可能转变为单芯片计算。最后，3D存储器沿着预期的未来垂直整合的总趋势发展得很好。