详细信息
分类信息:
>>学科导航分类法 _理学 _物理学 _凝聚态物理
封面图片 自有资源  
无权查看内容文件信息  
题名 Tb掺杂ZnO薄膜和高K栅介质Er2O3薄膜的制备及特性研究
姓名 方泽波
院系 物理科学与技术学院
专业 凝聚态物理
学位名称 理学博士
外文题名 The growth and properties of Tb-doped ZnO films and High k dielectric Er2O3 films
第一导师姓名 王印月
关键词 ZnO;透明导电薄膜;高K栅介质;Er2O3
外文关键词 ZnO;Transparent conductive films;high K dielectric;Er2O3
学科 理学
摘要 本论文主要包括两方面的内容:退火及Tb掺杂对ZnO薄膜结构,电学和光学特性的影响;硅基高K栅介质Er2O3薄膜的制备及特性研究。 ZnO是一种重要的宽带隙半导体材料。由于它在太阳能电池,压电器件,以及发光二极管等领域有广泛的应用前景。已经引起了许多研究者的关注,本论文第一部分主要研究了退火和Tb掺杂对多晶ZnO薄膜结构,电学及发光特性的影响。 采用射频反应溅射法,成功制备了高度取向的多晶ZnO薄膜,通过不同温度的退火处理,研究了退火对ZnO薄膜结构和发光特性的影响。由X射线衍射得知,随着退火温度的升高,晶粒逐渐变大,薄膜中压应力由大变小至出现张应力。PL测量显示样品在430 nm附近有一光致发光峰,这在国际上属首次发现。联合样品电阻率的变化及能级图,我们认为ZnO的蓝光发射主要来源于薄膜中的锌填隙原子缺陷。 用射频反应共溅射法在Si衬底上制备出了铽 (Tb) 掺杂ZnO透明导电薄膜。研究了Tb掺杂量和衬底温度对ZnO薄膜结构、电学和光学特性的影响。在最佳沉积条件下我们制备出良好C轴取向,电阻率为9.34 x 10-4 Ωcm,且可见光段平均透过率大于80 %的ZnO:Tb透明导电材料。通过对ZnO:Tb薄膜发光研究,我们认为ZnO:Tb可能在氧化物发光二极管中得到广泛的应用。关于ZnO:Tb的制备及应用研究,国际上还没有其他研究小组报道。 随着集成电路的发展,传统的SiO2栅介质正日益趋于它的极限。因此,各种各样的高k材料被用来研究作为SiO2栅介质的可能的替代物质。氧化铒由于具有较高的介电常数,大的带隙偏移和良好的化学稳定性被认为可能是一种很有应用前景的栅介质材料。 在本论文的第二部分里,我们主要研究高k栅介质Er2O3的生长及其特性。首先我们第一次实现了Er2O3薄膜在Si(100)和Si(111)衬底上的单晶生长。Er2O3薄膜在Si(100)上的外延关系为Er2O3(110)//Si(100)或者Er2O3(100)//Si(100)。Er2O3薄膜在Si(111)上的外延关系为Er2O3(111)//Si(111)。其次我们利用光电子能谱首次对Er2O3薄膜的能带偏移进行了研究。结果显示,Er2O3相对于Si的价带和导带偏移分别为3.1±0.1 eV和3.5±0.3 eV。Er2O3的禁带宽度为7.6±0.3 eV。 用反应蒸发方法成功制备了极薄Er2O3薄膜(~4.5 nm)。AES,XRD,RHEED和TEM测量分别证明了样品是化学剂量比,非晶结构的Er2O3薄膜。对于非晶Er2O3薄膜的制备,这在国际上尚属首次。对高真空退火样品的TEM测量,显示Er2O3薄膜具有良好的结构稳定性及陡峭的界面。通过对退火样品的C-V和I-V测试,我们获得了有效介电常数为12.6,有效氧化层厚度(EOT)为1.4 nm,在1 MV/cm的电场下漏电流密度为8×10-4 A/cm2的优质高介电常数材料。同时我们还系统地研究了氧气退火对非晶Er2O3薄膜的结构及电学特性的影响。我们的研究结果显示极薄非晶Er2O3薄膜可能是很好的高K栅介质材料。
外文摘要 Two parts are included in this dissertation: The growth and properties of Tb-doped ZnO films and high k dielectric Er2O3 films Zinc oxide (ZnO) are one of very useful materials and are used in piezoelectric device, transparent electrodes in photovoltaic and display, and light-emitting diodes. In this dissertation, we report the influence of the post–treatment on the structural and optical properties of reactive sputtering ZnO films, and Preparation of transparent conductive ZnO:Tb films and their photoluminescence properties. Polycrystalline ZnO films were prepared by reactive radio frequency sputtering (RF) technique with zinc target in the mixed gas of Ar and O2. The grain size increases with the annealing temperature. The photoluminescence (PL) spectra of these samples consist of one emission peak centered at 2.9 eV. This is first reported about the blue emission. It was proposed that the blue emission originated from the interstitial Zn. Tb-doped Zinc oxide (ZnO:Tb) films were prepared by RF reactive magnetron co-sputtering of a Zn target with some Tb-chips attached. The results show that the appropriate Tb ions incorporation into ZnO films can improve the structural and electrical properties of ZnO films. PL measurements show the characteristic emission lines corresponding to intra-4fn-shell transitions of Tb. Under the optimal conditions, the ZnO:Tb films with the low resistivity (ρ), the high transmittance at the visible region and the strong blue emission were prepared. The industry''''''''''''''''''''''''''''''''s demand for higher integrated circuit density and performance has forced the gated dielectric layer thickness to decrease rapidly. The use of conventional SiO2 films as gate oxide is reaching its limit. Therefore, a variety of alternative high-k materials are being investigated as possible replacements for SiO2. It has been reported that Er2O3 may be one of the most promising alternative dielectrics. However, there are no reported about growth of single crystal and amorphous Er2O3. In this thesis, we have studied the growth and characterization of high k materials Er2O3. The epitaxial growth of Er2O3 films on Si(100) and Si(111) have been investigated. The epitaxial relationship between Er2O3 and Si(100) substrate is as follows: Er2O3(110) // Si(100), or Er2O3(100) // Si(100). The epitaxial relationship between Er2O3 and Si(111) is Er2O3(111)//Si(111). The oxidized Si surface can suppress the formation of the silicide ph...
研究领域 微电子和光电子信息材料
保存本页    打印本页