Design of Circuits and Systems for Nonvolatile Nanomagnetic Logic

纳米磁逻辑（NML）是由纳米磁性点通过磁场耦合相互作用而组成的，因此是一种非电荷基的超CMOS技术。它可以提供非常密集、鲁棒和低功耗的集成系统，而不会产生泄漏电流。非易失性逻辑状态的可用性实现了即时开/关能力以及新的架构和功能。在我们目前的DFG项目“磁性多层膜中的场耦合电路”（2009-2012）中，与大多数其他小组不同，我们探索了一种使用具有垂直面外磁化的纳米磁体的NML技术。这产生了鲁棒且精确可控的开关行为、磁体的形状和布置的更多自由度以及最终更密集的布局。作为更新项目的起点，我们现在有了一种处理技术，我们可以设置单个点的切换阈值以及链和逻辑块中信号流的方向。我们已经通过实验验证了描述技术参数，几何形状和开关行为之间的依赖关系的模型。此外，我们还演示了反相器，扇出和多数门的基本逻辑功能，其中我们使用全局磁场作为时钟和能量供应。现在是时候进一步研究更复杂的电路和完整的系统架构了。为此，我们希望开发一个SPICE样的设备模型的磁化的单点和动态的时钟场的作用下与相邻的点耦合，以及行为模型用于更大的系统仿真。有了这个，我们将设计时钟和同步方案，包括缓冲电路对应的CMOS触发器。外部时钟字段的产生及其对电路行为的影响也将进行研究和优化。此外，我们希望利用现有的模型和测量数据来计算非理想工艺制造过程和热噪声导致的错误率，并研究稳健设计的方法以及可能的错误校正方案。作为一种全新的方法，我们建议使用z方向的垂直场耦合来创建真正的3D集成电路和系统。当使用多个功能层时，这提供了非常高的封装密度和非常灵活的架构。这项建议是基于我们自己的技术成功的试点实验。有了这个以及传统的2D布局，我们希望设计更大的系统，主要是算术逻辑单元和FPGA。由于NML在操作过程中固有的非易失性和可编程性，这些都从NML中获益匪浅，特别是3D集成，其中额外的一层可用于编程功能。

Nanomagnetic logic (NML), is composed of nanomagnetic dots interacting by magnetic field coupling, and thus is a non charge-based beyond CMOS technology. It can provide exceptionally dense, robust and low power integrated systems without leakage current. The availability of nonvolatile logic states enables instant on/off capability as well as new architectures and functionalities. In our current DFG project "Field-coupled circuits in magnetic multilayers" (2009-2012), different from most other groups we have explored a technology for NML that uses nanomagnets with perpendicular, out-of-plane magnetization. This gives rise to a robust and precisely controllable switching behavior, more degrees of freedom in shape and arrangement of the magnets, and finally a denser layout. As starting point for the renewal project, we have now a processing technology, where we can set the switching threshold of single dots and the direction of signal flow in chains and logic blocks. We have experimentally verified models describing the dependencies between technology parameters, geometry and switching behavior. Further we have demonstrated the basic logic functions of inverter, fan-out and majority gate, where we use a global magnetic field as clock and as energy supply. Now it is time to look further towards more complex circuits and complete system architectures. For that purpose we want to develop a SPICE-like device model for the magnetization of single dots and the dynamics of their coupling with neighbouring dots under action of the clocking field, as well as behavioral models to be used for larger system simulation. With this, we will design clocking and synchronization schemes, including buffer circuits corresponding to CMOS flipflops. The generation of the external clocking fields and their influence on the circuit behaviour will also be investigated and optimized. In addition, we want to use our existing models and measurement data to calculate error rates resulting from non-ideal technological manufacturing processes and thermal noise, and investigate methods for robust design as well as possible error correction schemes.As a completely new approach, we propose to use vertical field coupling in the z-direction for creation of true 3D integrated circuits and systems. This offers, when using several functional layers, a very high packing density and very flexible architectures. This proposal is based upon successful pilot experiments in our own technology. With this and also with the conventional 2D arrangement, we want to design larger systems, mainly an arithmetic logic unit and FPGAs. Those profit a lot from NML due to the inherent nonvolatility and programmability during operation, and especially from the 3D integration, where an extra layer can be used for the programming function.