基于新型纳米磁性薄膜提升超微片上电感高频特性的基础研究

With the popularization and development of high-speed mobile communication and the Internet of things technology, as an indispensable passive device in IC integrated circuits, on-chip inductors are becoming so smaller, higher frequency and performance. However, compared with the active device, on-chip inductor with all high integration, frequency and performance is still difficult to be achieved, seriously hindering the development of high-performance on-chip integration system. A new design of super-compact on-chip inductor with novel nano magnetic thin film is put forward in this project. Based on the basic requirements for magnetic materials applied on the on-chip, new kinds of nano magnetic thin films are selected. The preparation and optimization of materials, size and thickness of magnetic thin films will be generally analyzed, as well as high frequency characteristic test, in order to obtain magnetic film for the on-chip inductor applications. Based on high frequency characteristic analysis of nano magnetic thin film material, the equivalent circuit model of on-chip inductors will be established. And then combined with the HFSS electromagnetic and micro-magnetics simulation results, the effect of the physical mechanism of L, the quality factor Q , cut-off frequency f0 and fmax value of inductance will be revealed. By dint of the optimization of the complete device structure design and micro- and nano- fabrication technology, the optimal design way of on-chip inductors will be proposed. The exploration and development of high performance IC compatible inductor, can promote the application of device in intelligent electronic manufacturing, to meet the great demand of domestic related domain.

随着高速移动通讯以及物联网技术的推广与发展，作为集成电路中不可或缺的无源感性器件，片上电感需要向更小尺寸、更高频率、更低功耗方向发展。然而，与有源器件相比, 同时具有高集成度、高频率和高性能的片上电感依然难以实现，严重阻碍了片上集成系统的发展。本项目提出了基于新型纳米磁性薄膜提升超微片上电感高频特性的基础研究。从适于片上电感的磁性材料要求出发，以新型纳米磁性薄膜为研究对象，综合研究磁性薄膜的材料、尺寸和厚度的制备和优化，以及关键高频特性；并以此为基础，建立片上电感的等效电路模型；结合微磁学模拟结果和HFSS电磁仿真，揭示影响L、Q、f0、fmax等高频特性的物理机理；借助器件的结构设计和微纳加工技术的优化，提出最优的超微片上电感设计方式。探索和开发IC兼容的高性能片上电感，推动器件在智能电子制造中的应用，以满足国内相关领域的重大需求。

随着高速移动通讯以及物联网技术的推广与发展，作为集成电路中不可或缺的无源感性器件，片上电感需要向更小尺寸、更高频率、更低功耗方向发展。然而，与有源器件相比，同时具有高集成度、高频率和高性能的片上电感依然难以实现，严重阻碍了片上集成系统的发展。本项目基于新型纳米磁性薄膜开展超微片上电感高频特性的基础研究，主要包括：(1)磁性薄膜性能的优化和高频特性分析；(2)片上电感的设计及等效电路的建立；(3)微电感与磁性薄膜的片上集成。.重要结果及关键数据如下：重点研究了金属铁磁性薄膜CoFeB/ZnO/CoFeB，及铁氧体YIG薄膜的铁磁特性、高频特性以及材料的结构分析等，为片上微电感研究提供了材料基础。其中CoFeB(100 nm)/ZnO(5 nm)/CoFeB(100 nm)，其磁化强度Ms = 1.63T，矫顽力Hc = 33 Oe。当外加磁场H = 0 Oe，CoFeB/ZnO/CoFeB磁膜的铁磁共振频率（FMR）高达4 GHz，有助于片上射频电感在高频方面的应用。铁氧体YIG薄膜的矫顽力Hc = 0.5 Oe，且各向异性场Hk = 2498 Oe，有助于减小磁膜的磁损耗。以此为基础，结合优化的片上螺旋及背空电感结构设计，利用HFSS工具进行建立Π型等效电路，并对片上电感进行精确仿真。仿真及实验结果发现：同等条件下，背空结构设计的片上电感的最大品质因子要比常规电感能够提升约9%。对于最大品质因子Qmax时的频率fmax来说，背空电感的fmax = 3.7 GHz，而常规电感的fmax =仅为3.2 GHz。背空结构设计结合金属铁磁性薄膜CoFeB/ZnO/ CoFeB，使片上电感在频率为0 ~ 8 GHz的频段范围内，电感值提升了41.2% ~ 70.6%，并且在f = 6.9 GHz的时候实现了70.6%的提升。在0 ~ 3.8 GHz的频段范围内，品质因子Q提升量从3% ~ 18%，并且在f = 1.5 GHz时实现了18%的提升。另外，结合铁氧体YIG薄膜，将片上电感的应用频率提高到7.5 GHz，与以往C.Yang等、Scooter D. Johnson等人报道的结果相比，本项目实现了片上电感在应用频率上分别有400%, 87%和50%的提高。.本项目高频片上电感的成功制备为推动器件在智能电子制造中的应用奠定了材料、物理和器件基础。