不同氮流量比制备纳米Ta-N薄膜及其性能

超大规模集成电路Cu互连中的核心技术之一是制备性能优异的扩散阻挡层.本文采用直流磁控反应溅射在N2/Ar气氛中制备了不同组分比的Ta-N薄膜,并原位制备了Cu/Ta-N/基底复合结构,对部分样品在N2保护下进行了快速热处理(RTA),采用台阶仪、四探针测试仪、原子力显微镜(AFM)、扫描电镜、X射线衍射(XRD)对薄膜形貌结构进行了表征.结果表明,随着N2流量比的增加,薄膜沉积速率下降,表面趋于平滑,Ta-N薄膜热稳定性能及阻挡性能随之提高,而电阻率则上升.氮流量比为0.3制备的厚度为100nm的Ta-N薄膜经600℃/5min RTA后,仍可保持对Cu的有效阻挡;在更高温度下退火,Cu将穿过阻挡层与Si发生反应,导致阻挡层失效.     

SiCN扩散阻挡层薄膜的制备及特性研究

采用磁控溅射法在单晶硅衬底上制备了SiCN及Cu/SiCN薄膜,并对试样进行了退火处理.利用原子力显微镜(AFM)、X射线衍射(XRD)、四探针测试仪(FPP)研究了SiCN薄膜的表面形貌、物相结构及在Cu/SiCN/Si结构中SiCN薄膜对铜与硅的阻挡性能.结果表明,沉积态SiCN薄膜为无定型的非晶结构,晶化温度在1000℃以上;SiCN薄膜作为Cu的扩散阻挡层有较好的热稳定性及阻挡性,阻挡失效温度在600℃左右.     

N含量对Ta-Si-N扩散阻挡层阻挡性能的影响

采用磁控反应溅射技术在p型Si(111)衬底上制备了Ta-Si-N薄膜与Cu/Ta-Si-N复合结构,并对样品进行了快速热处理.用四探针电阻测试仪、原子力显微镜、X射线衍射和扫描电镜等对样品的电阻、形貌、结构与特性进行了分析表征.实验结果表明,随着N含量的增加,Ta-Si-N薄膜的方块电阻单调增加,表面粗糙度则先减小后增大;Ta-Si-N阻挡层的阻挡性能随N含量的增加而有所增强,但当N含量过大时,阻挡性能的提升并不明显;沉积态的Ta-Si薄膜为纳米晶结构,掺入N后,薄膜成为非晶态,但在高温热处理后Ta-Si-N薄膜重新结晶,铜原子主要通过晶界扩散并与Si反应,导致阻挡层失效.     

用于Cu互连的Ta/Ti-Al集成薄膜的结构和阻挡性能

应用射频磁控溅射法在(001)Si衬底上制备了Cu(120nm)/Ta(5nm)/Ti-Al(5nm)/Si异质结,借助原子力显微镜(AFM)、X射线衍射(XRD)和四探针测试仪(FPP)等方法研究了Ta(5nm)/Ti-Al(5nm)集成薄膜用作Cu和Si之间阻挡层的结构和性能。研究发现,Cu/Ta/Ti-Al/Si异质结即使经受850℃高温退火后,样品的XRD图中也没有出现杂峰,表明样品各层之间没有发生明显的化学反应。相对于800℃退火的样品,850℃退火样品的表面均方根粗糙度急剧增大,同时方块电阻也增加了一个数量级,表明Ta(5nm)/Ti-Al(5nm)集成薄膜在850℃时,阻挡性能完全失效。由于Ta和Cu之间存在良好粘附性以及Ti-Al强的化学稳定性,Ta(5nm)/Ti-Al(5nm)集成薄膜在800℃以下具有良好的阻挡性能。     

Cu互连中Ta/Ta-N和Ti/Ta-N双层膜的扩散阻挡性能比较

采用磁控溅射法在SiO2/Si基底上沉积Cu/Ta/Ta-N及Cu/Ti/Ta-N薄膜,在高纯的Ar/H2气氛保护下对样品进行快速热退火处理,用XRD、SEM、EDS及四探针电阻测试仪(FPP)等分析测试方法对Ta/Ta-N和Ti/Ta-N双层薄膜的热稳定性及互扩散阻挡性能进行了比较分析。结果表明,当退火温度低于700℃时,Cu/Ta/Ta-N/SiO2/Si和Cu/Ti/Ta-N/SiO2/Si多层膜结构表面平整,方阻值均比较小(Cu/Ta/Ta-N/SiO2/Si约为0.175Ω/□,Cu/Ti/Ta-N/SiO2/Si约为0.154Ω/□);当退火温度到达700℃时,Cu/Ta/Ta-N/SiO2/Si试样开始出现Ta2O5和Cu3Si,由于Cu向基底扩散打破Si-Si和Si-O键,Si、O经扩散通道分别与Cu、Ta反应生成了Cu3Si和Ta2O5,表明Ta/Ta-N阻挡层开始失效;而Cu/Ti/Ta-N/SiO2/Si试样的Cu/Ti相界面形成了很薄的扩散溶解层——Cu4Ti、Cu4Ti3与Cu3Ti2,有力地阻断Cu向基底扩散的通道,从而提高了Ti/Ta-N双层膜的阻挡性能,使Ti/Ta-N双层膜对Cu的有效阻挡温度高达700℃。因此,Ti/Ta-N双层膜是一种良好的扩散阻挡层。     

微波退火条件下镍和锗锡合金反应的形貌研究

为了研究高质量镍锗锡薄膜的制备方法,在不同微波退火温度下进行了锗锡合金与镍的固相反应。借助四探针方块电阻测试、原子力显微镜、透射电子显微镜、能量色散X射线光谱等表征手段,分析了在微波退火条件下100～350 ℃所生成镍锗锡化物样品的形貌。研究结果表明:镍锗锡化物的表层电阻、表面粗糙度及薄膜质量与微波退火温度紧密相关,在250 ℃退火条件下得到了连续平整的镍锗锡薄膜,锡偏析在镍锗锡/锗锡的界面;在350 ℃退火条件下,薄膜的连续性遭到破坏,表面粗糙度变大,锡偏析在样品的表面和镍锗锡/锗锡的界面。与常规快速热退火方式相比,本文采用的微波退火方式,可在相对更低的温度得到高质量的镍锗锡薄膜,降低了镍与锗锡衬底反应所需的热预算。     

SnO2退火温度对钙钛矿太阳能电池性能的影响

电子传输层是钙钛矿太阳能电池的关键部分, 起到阻挡空穴、传输电子和减少电子空穴复合的作用。本研究采用低温溶液法制备SnO₂薄膜作为钙钛矿电池的电子传输层, 研究SnO₂的退火温度对电子传输层微观形貌、物理性能以及钙钛矿太阳能电池性能的影响。结果表明: 当退火温度为60、90、120和240 ℃时, SnO₂薄膜表面存在较多的孔隙; 而退火温度为150、180和210 ℃时, 薄膜表面孔隙较少。在实验温度下, 制备的SnO₂薄膜为四方相, FTO玻璃上涂覆SnO₂薄膜后其透过率要优于空白FTO玻璃的透过率。当SnO₂退火温度为180 ℃时, 薄膜的电子迁移率最高, 钙钛矿电池具有最佳的传输电阻和复合电阻, 所得电池的性能最优, 其光电转换效率为17.28%, 开路电压为1.09 V, 短路电流为20.91 mA/cm², 填充因子为75.91%。     

纳米Ta-Al-N薄膜的制备及其扩散阻挡特性的研究

采用直流反应磁控溅射方法在P型（100）Si衬底上制备了Ta-Al—N纳米薄膜与Cu／Ta-Al—N复合膜，并对薄膜样品进行了卤钨灯快速热退火（RTP）。用四探针电阻测试仪（VPP）、AFM、SEM—EDS、Alpha—stepIQ台阶仪和XPd）等分析测试方法对样品的形貌结构与特性进行了分析表征。实验结果表明，本实验条件下制得的Ta-Al—N纳米薄膜表面光滑；随着Al靶溅射功率的增加，Ta-Al—N薄膜中Al含量和方块电阻相应增大，均方根粗糙度降低，而沉积速率变化不大，且Ta-Al—N膜层对Cu扩散的阻挡能力增强。但在过高的温度下退火，导致Cu通过Ta-Al—N的晶界扩散到Ta-Al—N／Si界面并形成Cu3Si，从而引起阻挡层的失效。     

反应磁控溅射制备氮化钽扩散阻挡层的研究

采用反应磁控溅射在硅衬底上制备了TaN薄膜,研究了氮分压、溅射功率及衬底温度对薄膜晶体结构、表面形貌和电学性能的影响。结果表明,晶体结构随工艺参数的改变发生变化,GIXRD图谱衍射峰强度随溅射功率和衬底温度的增加而增强,氮气分压的增加使择优取向向(111)晶面偏移;TaN薄膜的表面形貌与溅射功率和氮气分压密切相关,与衬底温度的关系不大,其粗糙度随溅射功率的增加而增大,随氮气分压的增加而减小;TaN薄膜的方块电阻随溅射功率的增加逐渐减小,随氮气分压的增加逐渐增大,温度对方块电阻的影响不大;对Cu/TaN/Si互联体系热处理后发现TaN薄膜具有优异的阻挡性能,在600℃时依然可有效阻止Cu向Si的扩散。     

C2H2流量对SiCN薄膜结构及阻挡性能的影响

采用C2H2和N2作为反应气体、多晶Si作为靶材,利用射频磁控溅射系统沉积了SiCN薄膜。利用傅里叶红外光谱仪、X射线衍射仪、四探针测试仪等研究了C2H2流量对薄膜结构、介电常数以及阻挡性能的影响。结果表明,薄膜为非晶结构,1000℃退火下未出现结晶,稳定性很好;随着C2H2流量的增大,薄膜表面颗粒呈现增大趋势;C原子取代Si原子占据薄膜中的网络位置,薄膜形成了以C-N键为主的网络结构;制得的SiCN薄膜介电常数在4.2~5.8之间,C,N含量以及薄膜结构是影响介电性能的关键因素,高温使得Cu穿过薄膜中的缺陷与Si发生互扩散是薄膜阻挡性能失效的主要原因。     

Thermal stability of magnetron sputtering amorphous carbon nitride films

Magnetron sputtered amorphous carbon nitride films were annealed at different temperatures (450-900°C) and time (30-120 min). Compositional, bonding structural and surface morphological modifications of the films were characterized by Fourier transformation infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy. The as-deposited film was found to have nitrogen content of 30 at%, and the carbon atoms were bonded to nitrogen atoms in the chemical structure state of CN, CN and CN bonds. The FTIR and XPS results showed that the films were thermally stable without an obvious change in the films as annealing temperature was lower than 600°C. The relative intensity ratio of CN over CN bonds reached a maximum at annealing temperature of 750°C, and then decreased gradually at annealing temperature up to 900°C. The CN bonds in the films decreased with the increase of annealing temperature and eliminated completely at annealing temperature of 900°C. These results revealed that annealing caused a substantial decrease in the number of weak bonds between carbon and nitride atoms. The CN bonds have higher thermal stability than CN bonds and CN bonds in the films. Simultaneously annealing also led to the formation of a large fraction graphitic-like carbon in the films while nitrogen escaped from the film. Besides, the surface roughness of the films increased with annealing temperature. However, when annealing time was increased from 30 to 120 min at annealing temperature of 750°C, only a slight effect of the annealing time on composition, bonding structure and the surface roughness of the films was observed.     

High thermal stability of AlCrTaTiZr nitride film as diffusion barrier for copper metallization

To inhibit rapid Cu diffusion in interconnect structures, an effective diffusion barrier layer with high thermal stability, low electrical resistivity and good interface adhesion is strongly demanded. Thus in this study, an amorphous nitride film of equimolar AlCrTaTiZr alloy with an N content of about 41 at.% was deposited by reactive radio-frequency magnetron sputtering. Thermal stability of the AlCrTaTiZr nitride film and its barrier property to Cu diffusion were investigated under thermal annealing at 700-900 °C. The AlCrTaTiZr nitride film remained an amorphous structure after thermal annealing at 700 °C and then crystallized at 800 °C. However, no interdiffusion between Si substrate and Cu metallization through the AlCrTaTiZr nitride film occurred. The electrical resistivity of the film remained at the low level of as-deposited value, indicating its good thermal stability as an effective diffusion barrier layer. With temperature further increasing to 900 °C, severe interdiffusion occurred, along with the formation of silicides and large pores. The electrical resistivity then significantly increased, implying the failure of the AlCrTaTiZr nitride film.     

退火温度对SmCo永磁薄膜微结构及磁性能的影响

采用直流磁控溅射法制备SmCo薄膜,研究了退火温度对薄膜微结构及磁性能的影响。XRD分析结果表明,当退火温度为600℃时,SmCo5相析出,而Sm2Co17相在700℃析出。SEM照片可看出,退火温度高于900℃时,六方柱状的SmCo5相和菱方状的Sm2Co17相全部析出。随着退火温度的升高,晶粒尺寸增大,当温度达940℃时,晶粒尺寸减小,而在980℃时,晶粒尺寸又将增大。VSM测试表明,与制备态的薄膜相比,退火后的薄膜在垂直于膜面方向的矫顽力、剩余磁化强度及最大磁能积都增大。960℃时得到矫顽力和剩余磁化强度的最大值,800℃时得到最大磁能积的最大值。     

不同温度下等离子渗氮后TC4钛合金的摩擦磨损性能EI北大核心CSCD

采用等离子渗氮技术提升TC4钛合金的耐磨性并探究最优渗氮温度。利用LDM 1-100型等离子渗氮设备,在650,700,750,800,850℃和900℃温度下对TC4钛合金进行渗氮处理,保温时间均为10 h。利用光学显微镜、扫描电子显微镜、白光三维形貌仪、X射线衍射仪和显微硬度计分别对不同温度渗氮试样的微观组织结构、表面形貌、表面粗糙度、相结构和硬度进行表征。利用CETR UMT-3型多功能摩擦磨损试验机测试等离子渗氮后TC4钛合金的摩擦学性能。结果表明:TC4钛合金表面显微硬度和粗糙度随温度升高而增大,在900℃渗氮后TC4钛合金表面显微硬度达到了1318HV 0.05,约为基体(360HV 0.05)的4倍。硬度的升高是由于渗氮后试样表面形成了硬质氮化物相(TiN和Ti2N相),且随着渗氮温度升高氮化物的含量增加。相较于低温渗氮(低于750℃)的试样,850℃和900℃渗氮试样的承载能力显著提升。与原始TC4试样相比,渗氮处理后试样的磨损体积显著降低。当渗氮温度为850℃时,试样磨损体积为未处理试样磨损体积的1.2%(1 N),3.0%(3 N)和62.2%(5 N),试样的耐磨性提升更为显著。     

N掺杂Cu2O薄膜的低温沉积及快速热退火研究

采用氧化亚铜(Cu_2O)陶瓷靶,利用射频磁控溅射沉积法在氮气和氩气的混合气氛下制备了N掺杂Cu_2O(Cu_2O∶N)薄膜,并在N_2气氛下对薄膜进行了快速热退火处理,研究了N_2流量和退火温度对Cu_2O∶N薄膜的生长行为、物相结构、表面形貌及光电性能的影响。结果显示,在衬底温度300℃、N_2流量12sccm条件下生长的薄膜为纯相Cu_2O薄膜;在N_2气氛下对预沉积薄膜进行快速热退火处理不影响薄膜的物相结构,薄膜的结晶质量随退火温度(450℃)的升高而显著改善;快速热退火处理能改善薄膜的结晶质量和缺陷,降低光生载流子的散射,增强载流子的传输,预沉积Cu_2O∶N薄膜经400℃退火处理后展示出较好的电性能,薄膜的霍尔迁移率(μ)为27.8cm~2·V~(-1)·s~(-1)、电阻率(ρ)为2.47×10~3Ω·cm。研究表明低温溅射沉积和快速热退火处理能有效改善Cu_2O∶N薄膜的光电性能。     

Oxidation behaviour of Ti2AIN films composed mainly of nanolaminated MAX phase

In this paper, we reported the oxidation behaviour of Ti2AIN films on polycrystalline Al2O3 substrates. The Ti2AIN films composed mainly of nanolaminated MAX phase was obtained by first depositing Ti-Al-N films using reactive sputtering of two elemental Ti and Al targets in Ar/N2 atmosphere and subsequent vacuum annealing at 800 degrees C for 1 h. The Ti2AIN films exhibited excellent oxidation resistance and thermal stability at 600-900 degrees C in air. Very low mass gain was observed. At low temperature (600 degrees C), no oxide crystals were observed on film surface. Blade-like Theta-Al2O3 fine crystals formed on film surfaces at 700-800 degrees C. At high temperature (900 degrees C), firstly Theta-Al2O3 formed on film surface and then transformed into alpha-Al2O3. At 700-900 degrees C, a continuous Al2O3 layer formed on Ti2AIN films surface, acting as diffusion barrier preventing further oxidation attack. The mechanism of the excellent oxidation resistance of Ti2AIN films was discussed based on the experimental results.     

Influence of thermal annealing on optical properties and structure of aluminium oxide thin films by filtered cathodic vacuum arc

Optical and structural properties of aluminium oxide thin films are investigated in the annealing temperature range of 200–900 °C. The changes in optical properties and film structure show the great dependence on the temperature. For the film annealed at low temperatures (from 200 °C to 600 °C), the film optical properties, such as transmittance and optical constants, could be improved by thermal annealing with amorphous structure and smooth surface. However, for the film annealed at higher temperature (e.g. 900 °C), the poor performance of optical properties indicates undesirable application for precise use in optics due to significant changes in both structure and surface roughness. At optimum annealing temperature of 600 °C, the transmittance could reach as high as that of substrate and the film possesses better optical constants (refractive index was 1.73 and extinction coefficient was ∼10⁻⁴ at 550 nm) with remaining amorphous structure and smooth surface.     

SiNx薄膜中硅纳米粒子的制备及表征

通过等离子增强化学气相沉积(PECVD)法, 以氨气和硅烷为反应气体, P型单晶硅和石英为衬底, 低温下(200℃)制备了含硅纳米粒子的非化学计量比氮化硅(SiN_x)薄膜. 经高温(范围500~950℃)退火处理优化了薄膜结构. 室温下测试了不同温度退火后含硅纳米粒子SiN_x薄膜的拉曼(Raman)光谱、光致发光(PL)光谱及傅立叶变换红外吸收(FTIR)光谱, 对薄膜材料的结构特性、发光特性及其键合特性进行了分析. Raman光谱表明. SiN_x薄膜内的硅纳米粒子为非晶结构. PL光谱显示两条与硅纳米粒子相关的光谱带, 随退火温度的升高此两光谱带峰位移动方向相同. 当退火温度低于800℃时, PL光谱峰位随退火温度的升高而蓝移. 当退火温度高于800℃时, PL光谱峰位随退火温度的升高而红移. 通过SiNx薄膜的三种光谱分析发现薄膜的光致发光源于硅纳米粒子的量子限制效应. 这些结果对硅纳米粒子制备工艺优化和硅纳米粒子光电器件的应用有重要意义.     

碳化硼球面薄膜及空心微球的制备

采用电子束蒸发镀膜技术, 结合磁控滚动方法在Φ1 mm的钢球基底上制备碳化硼球面膜层, 通过退火、打孔及腐蚀获得碳化硼空心微球. 主要研究了球面膜层的宏观形貌、微观结构、成分及初步探讨了不同退火温度(800~1100℃)对核膜结构空心化的影响. 利用扫描电子显微镜(SEM)、X射线光电子能谱分析(XPS)、原子力显微镜(AFM)对球面薄膜表面形态和薄膜元素组成进行了分析. 结果表明: 磁控滚动模式制备的球面膜层表面平整, 没有裂纹和孔洞, 元素分布均匀. 核膜结构(镀膜时间在5~70 h)经900℃以上温度退火, 空心化后的球面膜层可实现自支撑, 900℃退火的微球表面形貌最好, 壁厚可达10 μm以上.