CAREER:Doped Aluminum Nitride Ferroelectric Microelectromechanical Systems

职业：掺杂氮化铝铁电微机电系统

• 批准号: 1944248
• 负责人: Roy Olsson
• 金额: $ 50万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1944248&HistoricalAwards=false
• 关键词: CAREER; Doped; Aluminum; Nitride; Ferroelectric

Proposal Title:CAREER: Doped Aluminum Nitride Ferroelectric Microelectromechanical SystemsNontechnical AbstractIn cellular phones, piezoelectric materials convert radio frequency signals into mechanical vibrations that form the miniature, highly selective, front-end filters critical to efficient utilization of the radio-frequency (RF) spectrum. While acoustic filter technologies are well developed in the existing cellular bands, miniature filtering technologies for mitigating interference are lacking in the Millimeter Wave bands that have been allocated for broadband fifth-generation (5G) cellular network technology. The proposed research will study new methods for scaling the frequency of acoustic front-end filtering technologies to the Millimeter Wave bands without the degradation in performance that plaques existing frequency scaling approaches. Success of the proposed research will enable reliable fifth-generation wireless networks that are more robust to interference. The applications will have major societal impacts.Technical AbstractThere are two grand challenges to overcome in acoustic filter technologies as they are scaled to meet the needs of wireless communication systems, such as fifth-generation (5G) mobile networks. First, as the frequency of acoustic resonators and filters are scaled beyond 6 giga Hertz (GHz), the dimensions rapidly shrink, significantly degrading the performance due to a litany of parasitic effects. These including degradation of the resonator quality factor arising from scattering at the resonator surfaces and from resistive losses in the thinned metal electrodes, and degradation of the resonator electromechanical coupling as the ratio of the device capacitance falls in comparison to the capacitance associated with on-chip routing to the tiny acoustic devices. Second, the fixed frequency operation of existing acoustic resonators limits the number of bands that can be added before the losses, area, and cost introduced by the routing and switches becomes unworkable. This research seeks to study and exploit the recently discovered ferroelectricity in aluminum scandium nitride (AlScN) thin films to address these fundamental challenges. The proposed research will develop material deposition techniques allowing for the systematic tailoring of the ferroelectric properties through the thickness of an aluminum scandium nitride film stack via variations in scandium doping. These techniques will be utilized to form film stacks where the coercive fields have been engineered to vary through the device thickness, allowing for the selective inversion of the ferroelectric polarization of specific regions in the aluminum scandium nitride films at controllable depths. Periodically poled layers through the film thickness will be realized to selectively excite high order overtone acoustic resonances that enable dramatic frequency scaling without the steep reductions in resonator dimensions that degraded both the quality factor and electromechanical coupling of prior frequency scaling attempts. The selective poling techniques will be extended to demonstrate acoustic resonators that can be dynamically reconfigured over many octaves in frequency. Finally, fundamental questions pertaining to the aluminum scandium nitride film properties that ultimately define the performance limits of the proposed radio-frequency (RF) devices will be explored.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.

提案标题：职业：掺杂的氮化铝铁电微电机电系统非技术摘要摘要细胞手机，压电材料将射频信号转换为机械振动，形成微型，高度选择性，高度选择性的前端过滤器至关重要的，至关重要的前端过滤器，从而有效地利用了广播效率（RFEFEREQUENCY（RF）（RF）（RF）。尽管在现有的细胞频段中发达了声学滤波器技术，但在已经分配给宽带第五代（5G）细胞网络技术的毫米波带中缺乏用于减轻干扰的微型滤波技术。拟议的研究将研究将声学前端滤波技术缩放到毫米波带的新方法，而没有斑块现有频率缩放方法的性能下降。拟议的研究的成功将使可靠的第五代无线网络对干扰更强大。这些应用程序将产生重大的社会影响。技术抽象是在声学滤波器技术中缩放的两个巨大挑战，可以满足无线通信系统的需求，例如第五代（5G）移动网络。首先，随着声学谐振器和过滤器的频率超过6 giga hertz（GHz），尺寸迅速缩小，由于一系列寄生效应而引起的性能大大降低了。这些包括在谐振表面散射以及稀薄的金属电极中的电阻损耗以及谐振器机电耦合的降解所产生的谐振质量因子的降解，这是设备电容的比率与与机队的相比，其与机芯相比的比率下降了，而脱位均匀。其次，现有声音谐振器的固定频率操作限制了可以在路由和开关引入的损失，区域和成本之前可以添加的频段数量。这项研究旨在研究和利用最近发现的氮化铝（ALSCN）薄膜中发现的铁电性，以应对这些基本挑战。拟议的研究将开发材料沉积技术，从而通过氧化铝氧化铝膜层的厚度通过scandium掺杂的变化来实现铁电特性的系统调整。这些技术将用于形成薄膜堆栈，在该薄膜堆栈中，该技术已设计为通过设备厚度变化，从而可以选择性地反转氮化铝菌膜中特定区域的铁电化极化。定期通过膜厚度的螺旋层将被实现，以选择性地激发高阶的高阶声音共振，从而在谐振器尺寸的急剧下降低，从而降低了质量因子和机电耦合先前的频率缩放尝试。选择性极点技术将扩展，以演示可以在许多八度频率上动态重新配置的声学谐振器。最后，将探索与铝制氮化铝业膜有关的基本问题，这些问题最终定义了拟议的广播设备（RF）设备的性能限制。该奖项反映了NSF的法定任务，并通过评估该基金会的智力优点和广泛的影响来评估NSF的法定任务，并被认为值得通过评估。

项目成果

Controlling Residual Stress and Suppression of Anomalous Grains in Aluminum Scandium Nitride Films Grown Directly on Silicon

• DOI: 10.1109/jmems.2022.3167430
• 发表时间: 2022-05-06
• 期刊: JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
• 影响因子: 2.7
• 作者: Beaucejour, Rossiny;Roebisch, Volker;Olsson, Roy H., III
• 通讯作者: Olsson, Roy H., III

Sub-quarter micrometer periodically poled Al0.68Sc0.32N for ultra-wideband photonics and acoustic devices

• DOI: 10.1063/5.0161423
• 发表时间: 2023-09-21
• 期刊: JOURNAL OF APPLIED PHYSICS
• 影响因子: 3.2
• 作者: Tang，Zichen;Esteves，Giovanni;Olsson，Roy H.
• 通讯作者: Olsson，Roy H.

Strongly enhanced second-order optical nonlinearity in CMOS-compatible Al 1−x Sc x N thin films

CMOS 兼容的 Al 1–x Sc x N 薄膜中二阶光学非线性得到显着增强

• DOI: 10.1063/5.0061787
• 发表时间: 2021
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: Yoshioka, Valerie;Lu, Jian;Tang, Zichen;Jin, Jicheng;Olsson, Roy H.;Zhen, Bo
• 通讯作者: Zhen, Bo