ULSI硅衬底的化学机械抛光

在分析ULSI中硅衬底CMP的动力学过程基础上,提出了在机械研磨去除产物过程中,适当增强化学作用可显著改善产物的质量传输过程,从而提高抛光效率.在对不同粒径分散度的硅溶胶抛光液进行比较后提出了参与机械研磨的有效粒子数才是机械研磨过程的重要因素,而不是单纯受粒径大小的影响.分析和讨论了CMP工艺中的几个影响因素,如粒径大小与分散度、pH值、温度、流量和浓度等.采用含表面活性剂和螯合剂的清洗液进行抛光后清洗,表面颗粒数优于国际SEMI标准,抛光雾得到了有效控制.     

Synthesis of monoclinic structure gallium oxide film on sapphire substrate by magnetron sputtering

Gallium oxide (Ga2O3) films were deposited on singlecrystalline sapphire (0001) substrate by radio frequency (RF) magnetron sputtering technique in the temperature range of 300—500 °C. The microstructure of the β-Ga2O3 films were investigated in detail using X-ray diffractometer (XRD) and scanning electron microscope (SEM). The results show that the film prepared at 500 °C exhibits the best crystallinity with a monoclinic structure (β-Ga2O3). Structure analysis reveals a clear out-of-plane orientation of β-Ga2O3 || Al2O3 (0001). The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared (UV-vis-NIR) spectrophotometer. Therefore, it is hopeful that the β-Ga2O3 film can be used in the UV optoelectronic devices. #$TABThis work has been supported by the National Natural Science Foundation of China (Nos.61274113, 61404091, 61505144, 51502203 and 51502204), the Opening Fund of Key Laboratory of Silicon Device Technology in Chinese Academy of Sciences, and the Tianjin Natural Science Foundation (Nos.14JCZDJC31500 and 14JCQNJC00800).#$TABE-mail:miwei1986@yeah.net      

层状二硫化钼研究进展

近年来,层状二硫化钼由于其特殊的类石墨烯结构和独特的物理化学性质已成为国内外研究的热点.本文综述了层状二硫化钼的物理结构、价带结构和光学性质;介绍了制备方法,包括生长制备和剥离制备.生长制备的原料包括四硫代钼酸铵((NH4)_2MoS_4)、钼(Mo)和三氧化钼(MoO_3)等.剥离制备包括微机械剥离、液相超声法、锂离子插层法和电化学锂离子插层法等.归纳了层状二硫化钼在场效应晶体管、传感器和存储方面的应用,展望了层状二硫化钼的研究前景.     

Influence of annealing on the structural,optical and electrical properties of indium oxide films deposited on c-sapphire substrate

Indium oxide (In₂O₃) films were prepared on Al₂O₃ (0001) substrates at 700 °C by metal-organic chemical vapor deposition (MOCVD). Then the samples were annealed at 800 °C, 900 °C and 1 000 °C, respectively. The X-ray diffraction (XRD) analysis reveals that the samples were polycrystalline films before and after annealing treatment. Triangle or quadrangle grains can be observed, and the corner angle of the grains becomes smooth after annealing. The highest Hall mobility is obtained for the sample annealed at 900 °C with the value about 24.74 cm²·V^-1·s^-1. The average transmittance for the films in the visible range is over 90%. The optical band gaps of the samples are about 3.73 eV, 3.71 eV, 3.70 eV and 3.69 eV corresponding to the In₂O₃ films deposited at 700 °C and annealed at 800 °C, 900 °C and 1 000 °C, respectively.     

Analysis of the resistive switching behaviors of vanadium oxide thin film

We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer(Agilent B1500A),and the relative micro-analysis of I-V characteristics of VOx/Cu is characterized by using a conductive atomic force microscope(CAFM).The I-V test results indicate that both the forming and the reversible resistive switching between low resistance state(LRS) and high resistance state(HRS) can be observed under either positive or negative sweep.The CAFM images for LRS and HRS directly exhibit evidence for the formation and rupture of filaments based on positive or negative voltage.The Cu/VOx/Cu sandwiched structure exhibits reversible resistive switching behavior and shows potential applications in the next generation of nonvolatile memory.     

新型铜互连方法——电化学机械抛光技术研究进展

多孔低介电常数的介质引入硅半导体器件给传统的化学机械抛光(CMP)技术带来了巨大的挑战,低k介质的脆弱性难以承受传统CMP技术所施加的机械力.一种结合了电化学和机械平坦化技术的新颖铜平坦化工艺--电化学机械抛光(ECMP)应运而生,ECMP在很低的压力下实现了对铜的平坦化,解决了多孔低介电常数介质的平坦化问题,被誉为未来半导体平坦化技术的发展趋势之一.主要综述了电化学机械抛光技术的产生、原理、研究进展和展望,对铜的ECMP技术进行了回顾和讨论.     

氧化钒薄膜的微结构及阻变特性研究

采用射频反应溅射法于室温下在Cu/Ti/SiO₂/Si基底上制备了氧化钒薄膜. X-射线衍射、X射线光电子能谱分析仪及原子力显微镜结果表明, 室温下制备的氧化钒薄膜除微弱的V₂O₅ (101)和V₂O₃ (110)峰外, 没有明显的结晶取向, 是VO₂, V₂O₅, V₂O₃及VO的混合相薄膜, 且薄膜表面颗粒大小均匀, 表面均方根粗糙度约为1 nm. 采用半导体参数分析仪对薄膜的电开关特性进行测试. 结果表明薄膜具有较低的开关电压(V_Set<1 V, V_Reset<-0.5 V), 并且具有稳定的可逆开关特性. 薄膜从低阻态转变为高阻态的电流(I_Reset)随限流的增大而增大.通过高低阻态时I-V对数曲线的拟合(高阻态斜率>1, 低阻态斜率=1), 认为Cu离子在薄膜中扩散形成的导电细丝是该体系发生电阻转变的主要机制. 关键词： 氧化钒薄膜 电阻开关 电阻式非挥发存储器 导电细丝     

Damascene Array Structure of Phase Change Memory Fabricated with Chemical Mechanical Polishing Method

A damascene structure of phase change memory （PCM） is fabricated successfully with the chemical mechanical polishing （CMP） method, and the CMP of Ge2Sb2Te5 （GST） and Ti films is investigated. The polished surface of wafer is analysed by scanning electron microscopy （SEM） and an energy dispersive spectrometer （EDS）. The measurements show that the damascene device structure of phase change memory is achieved by the CMP process. After the top electrode is deposited, dc sweeping test on PCM reveals that the phase change can be observed. The threshold current of array cells varies between 0.90mA and 1.15mA.     

硅衬底超精密CMP中抛光液的研究

针对硅衬底的化学机械抛光,采用自制的大粒径硅溶胶抛光液进行抛光实验,研究了抛光液中主要组分对抛光速率和表面平整度的影响,以提高抛光速率和抛光质量,采用测厚仪、AFM、台阶仪对抛光速率和表面进行了测试和表征.通过优化实验获得了高速率、高平整的抛光表面.去除速率(MRR)达697nm/min,表面粗糙度(RMS)降低至0.4516nm,在提高抛光速率的同时对硅片实现了超精密抛光.     

硅晶片双面超精密化学机械抛光

为提高硅晶片双面超精密抛光的抛光速率，在分析双抛工艺过程基础上，采用自制大粒径二氧化硅胶体磨料配制了SIMIT8030-I型新型纳米抛光液，在双垫双抛机台上进行抛光实验. 抛光液、抛光前后厚度、平坦性能及粗糙度通过SEM、ADE-9520型晶片表面测试仪、AFM进行了表征. 结果表明：与进口抛光液Nalco2350相比，SIMIT8030-I型抛光液不仅提高抛光速率40% (14μm/h vs 10μm/h) ；而且表面平坦性TTV和TIR得到改善；表面粗糙度由0.4728nm降至0.2874nm，即提高抛光速率同时显著改善了抛光表面平坦性和粗糙度.