【作者】 崔健；

【导师】 杨保和；

【作者基本信息】 天津理工大学 ， 物理电子学， 2007， 硕士

【摘要】 声表面波(SAW)器件具有小型化、高可靠、多功能、一致性好等特点,所以它在雷达、电子战、声纳、无线通信、光纤通信及广播电视系统中正在获得广泛的应用。声表面波滤波器工作频率f由声表面波传播速度V和叉指周期长度L决定,即f=V/L。近年来,大量数据传输和移动通信的增加,通信频带向高频方向扩展,急需高频声表面波(SAW)滤波器,由于所采用的材料和加工工艺的限制,目前的声表面波器件其工作频率很难达到GHz。金刚石具有非常高的声表面波速度,以它为衬底制作的声表面波器件工作频率很容易达到GHz,且具有很多优点,因此利用金刚石作为衬底制作多层膜SAW滤波器已成为国际上的一个热点。本文围绕ZnO/IDT/Diamond多层膜结构GHz级声表面波滤波器的研制,主要就适于SAW滤波器的高声速传播载体金刚石基底的制备进行了研究,采用MPCVD技术制备出了金刚石薄膜,并利用XRD、SEM、Raman等测试手段对薄膜进行了表征分析。由于论文侧重点的不同,有关ZnO压电薄膜的制备本课题组采用磁控溅射生长法,具体请见我的合作伙伴的论文。围绕高频SAW滤波器的研制,本文作了以下工作:首先,对多层膜结构SAW滤波器的原理进行了阐述;其次,1、采用MPCVD技术在<100>镜面抛光硅片表面异质外延生长了金刚石薄膜,采用XRD, SEM, Raman等测试手段对薄膜进行了分析,表明此外延生长的薄膜为<004>高定向的质量较高的金刚石薄膜;2、研究了在不同类型Si衬底上金刚石的生长。分别在<100>、<111>两种不同类型Si衬底上生长了金刚石薄膜,利用XRD测试分析,表明采用不同类型的衬底对金刚石生长的取向有所影响;3、研究了沉积温度对金刚石取向的影响。分别在较高和较低温度下制备出了金刚石薄膜,在较高温度下生长的金刚石薄膜呈正六面体形,在沉积温度降低时,金刚石由正六面体向正八面体转化;4、在金刚石生长过程中,金刚石晶粒不能柱状生长无限长大,各个取向晶粒互相抑制,生长过程中达到一个稳定的大小。本文结合测试结果,对金刚石晶体的生长机理进行了初步的探索;此外,对声表面波滤波器的设计方法进行了简要的介绍。总之,通过一系列的研究,本文研究了沉积工艺对薄膜性能的影响,并进一步对CVD的机理进行了初步的探索,为下一步制作ZnO/IDT/Diamond多层膜结构声表面波滤波器奠定了基础。更多还原

【Abstract】 Surface Acoustic Wave (SAW) Device has the characteristic of mini capacity, high reliability, multiple-function and good coherence, so it have being used widely in the scope of radar, electronic battle, sonar, wireless communication, optic communication and broadcast system.Center frequency of SAWF was decided by SAW velocity V and the IDT’s cycle-width L, that is f=V/L. Now, with transport of mass data and increasing of mobile communication, communication frequency band extend to high frequency and high-frequency SAW filter was urgently needed. Because of the limitation of material and process technology, it is hard to reach GHz frequency for general SAWF. Diamond has much high velocity of SAW, so the SAWF adopted diamond as underlay can easily reach GHz frequency and it turns to be a hotspot in international.Because of different emphasize point in our task-team, this thesis mostly studied on diamond deposition which fit SAW filter. ZnO/IDT/Diamond multi-film SAW filter require diamond film has smooth surface, low vice density and so on, in order to be advantageous to deposit aluminium film to fabricate IDT. Because the IDT was very thin, it required the diamond film surface has high smooth rate in order to minish insert-waste and low vice density to minish transmit-waste.Surround manufacture of SAW device, this thesis do these works as follows:First, expatiate the theory of multi-film SAW device;Second,1, Adopting MPCVD skill, we deposited diamond film on <100> mirror-polished Si flake. Using XRD, SEM, Raman testing method, we proved this film to be <004> high tropism and high quality diamond film.2, Studyed diamond’s growth on different type Si flake, XRD spectrum indicate that on <111>Si flack, the diamond film growed has relatively more <111> tropism.3, Studyed influence of temperature to diamond tropism. With temperature fall, the shape of diamond transform from hexahedron to octahedron.4, In the process of growth, diamond crystal can not grow more and more big infinitely like column, with restrain of different tropism crystal, it reach a steady size. In this thesis, we also explored diamond growth mechanism elementarily.Besides, introduced designing method of SAW filter briefly.To sum up, through a series of study, this thesis studied influence to diamond growth adopting different deposition teachnology and do some elementary exploration to CVD mechanism, established foundation to next step to facture SAWF of ZnO/IDT/Diamond structure.更多还原