Monolithically Integrated Tunable ZnO SAW Chip

单片集成可调谐 ZnO SAW 芯片

• 批准号: 0088549
• 负责人: Yicheng Lu
• 金额: $ 50.99万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0088549&HistoricalAwards=false
• 关键词: Monolithically; Integrated; Tunable; ZnO; SAW

This proposed research focuses on the materials growth, device design and fabrication, andapplications of a ZnO monolithically integrated tunable surface acoustic wave (MITSAW) chip. Thenovel chip integrates acoustic, optical and electrical process' in one material system. It uses tunableacousto-electric and acousto-optic interaction between surface acoustic waves (SAW) and a twodimensional electron gas (2DEG) in a ZnO/MgxZn1-xO quantum well.ZnO is a multifunctional material possessing unique electrical, optical, acoustical, and mechanicalproperties. The high electromechanical coupling coefficients of piezoelectric ZnO in conjunction with thelow acoustic loss and high velocity of sapphire (Al2O3) offers high frequency and low loss RFapplications. Alloying ZnO with MgO forms the ternary compound MgxZn1-xO, which permits band-gaptuning from 3.32 eV to 4 eV. ZnO/MgxZn1-xO heterostructures with 2DEG can be integrated with SAW tocreate a unique acoustic velocity tuning mechanism. The 2DEG interacts with the lateral electric fieldresulting in ohmic loss, which attenuates and slows the surface acoustic wave. This mechanism is used totune the acoustic velocity. The high coupling coefficients offered by the ZnO/R-Al2O3 systems allowsvelocity tuning up to 1%. Combined with the optical characteristics of the wide and direct band gap(~3.3eV) semiconductor ZnO and transparent conductive ZnO electrodes, the MITSAW chip can be usedfor UV optical signal processing. The proposed MITSAW consists of a ZnO/MgxZn1-xO quantum wellstructure grown on a R-plane sapphire (R-Al2O3) substrate using MOCVD. R-plane sapphire is choseninstead of the popular C-plane substrate, as this substrate provides in-plane anisotropy in the ZnO layer.By aligning the device parallel to the c-axis of the ZnO film, Rayleigh type surface acoustic waves areexcited, while Love type SAWs are excited when the devices are aligned perpendicular to the c-axis. TheRayleigh wave mode is suitable for gaseous environment sensing, while the Love wave mode, which hasno vertical wave component, is ideal for liquid environment sensing. The ZnO MITSAW chip also offersan acoustic-optical dual mode sensing mechanism. Likewise, the optical properties parallel andperpendicular to the c-axis are different, allowing novel optical devices, such as high contrast modulators,to be fabricated.The successful development of the ZnO MITSAW chip technology will provide industry withstate-of-the-art new multifunctional chip technologies. It will not only improve the existing devices butalso develop fundamentally new approaches to many important application areas, includingtunable/adaptive communication systems, novel multi-mode tunable chemical and biochemical sensors,and optical signal processors such as delay lines and multiplexers.

本研究重点关注 ZnO 单片集成可调谐表面声波 (MITSAW) 芯片的材料生长、器件设计和制造以及应用。这种新颖的芯片将声学、光学和电学过程集成在一个材料系统中。它利用 ZnO/MgxZn1-xO 量子阱中表面声波 (SAW) 和二维电子气 (2DEG) 之间的可调谐声电和声光相互作用。ZnO 是一种多功能材料，具有独特的电学、光学、声学和机械性能。压电 ZnO 的高机电耦合系数与蓝宝石 (Al2O3) 的低声损耗和高速度相结合，可提供高频和低损耗 RF 应用。将 ZnO 与 MgO 合金化形成三元化合物 MgxZn1-xO，允许带隙从 3.32 eV 调整到 4 eV。具有 2DEG 的 ZnO/MgxZn1-xO 异质结构可以与 SAW 集成，以创建独特的声速调谐机制。 2DEG 与横向电场相互作用，导致欧姆损耗，从而衰减并减慢表面声波。该机制用于调节声速。 ZnO/R-Al2O3 系统提供的高耦合系数允许速度调节高达 1%。结合宽直接带隙（~3.3eV）半导体ZnO和透明导电ZnO电极的光学特性，MITSAW芯片可用于紫外光信号处理。所提出的 MITSAW 由使用 MOCVD 在 R 平面蓝宝石 (R-Al2O3) 基板上生长的 ZnO/MgxZn1-xO 量子阱结构组成。选择 R 面蓝宝石代替流行的 C 面衬底，因为该衬底在 ZnO 层中提供面内各向异性。通过将器件平行于 ZnO 薄膜的 c 轴对齐，可以激发瑞利型表面声波，同时当器件垂直于 c 轴排列时，Love 型 SAW 会被激发。瑞利波模式适合气体环境传感，而洛夫波模式没有垂直波分量，非常适合液体环境传感。 ZnO MITSAW 芯片还提供声光双模式传感机制。同样，平行和垂直于c轴的光学特性也不同，从而可以制造新型光学器件，例如高对比度调制器。ZnO MITSAW芯片技术的成功开发将为业界提供最先进的新光学器件。多功能芯片技术。它不仅会改进现有设备，而且还会为许多重要应用领域开发全新的方法，包括可调谐/自适应通信系统、新型多模式可调谐化学和生化传感器以及延迟线和多路复用器等光信号处理器。