TaN薄膜原子层淀积

我们成功合成了TaN薄膜原子层淀积的高纯有机钽先驱物并使其特性化,同时对这些先驱物的汽压和热稳定性进行了研究。根据汽压分析发现,TBTEMT比所有其它已发表的液体TaN先驱物(包括TBTDET、TAITMATA和IPTDET)具有更高的汽压。用1HNMR技术研究了这些烷基先驱物的热稳定性。结果表明,与乙二烯基先驱物相比,对于TBTDET和TBTEMT材料,特丁基群是最稳定的基群。TaN先驱物热稳定性按以下次序下降:TBTDET>PDMAT>TBTEMT。最后,通过对金属中央周围的配合基体进行轻微的调整使先驱物汽压和热稳定性处于良好的状态。     

Chemical vapor deposition of tantalum nitride films for metal gate application using TBTDET and novel single-source MOCVD precursors

In this paper, physical and electrical properties of TaN films used as metal electrodes in MOS structures are discussed. TaN films were deposited by MOCVD from commercial TBTDET and two novel mixed amido/imido/guanidinato and mixed amido/imido/hydrazido precursors. It will be shown that morphology (only films deposited from the guanidinato compound above 750 °C showed cubic TaN phase while all other films were amorphous) and O content (5 at.% and 25 at.% in case of guanidinato and in case of TBTDET precursor, respectively) do not necessary predetermine resistivity. Lowest resistivity (230 μΩ cm) was obtained for TBTDET. Evaluated values of metal work function are 4.4–4.6 eV (TBTDET) and 3.9 eV (guanidinato compound). Films deposited from the hydrazido compound reveal bad electrical properties (e.g., metal layers behave dielectric-like).     

Study of diffusion barrier properties of ionized metal plasma (IMP) deposited TaN between Cu and SiO2

The diffusion barrier properties of IMP deposited TaN between Cu and SiO₂ have been investigated in the Cu (200 nm)/TaN (30 nm)/SiO₂ (250 nm)/Si multi-layer structure. The IMP-TaN thin film shows better Cu diffusion barrier properties than chemical vapor deposition (CVD) and conventional physical vapor deposition (PVD) deposited TaN films. The thermal stability was evaluated by electrical measurement and X-ray diffraction (XRD) analysis. As a main part of thermal stability studies, the atomic intermixing, new compound formation and phase transitions in the test structure were also studied. Furthermore, a failure mechanism was also examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), secondary ion mass spectroscopy (SIMS) and Rutherford backscattering spectroscopy (RBS) in conjunction with electrical measurements. The 30 nm thick IMP-TaN was found to be stable up to 800°C for 35 min.     

超薄Ru/TaN双层薄膜作为无籽晶铜互连扩散阻挡层

研究了钌（Ru) /氮化钽（TaN）双层结构对铜的扩散阻挡特性，在Si (100）衬底上用离子束溅射的方法沉积了超薄Ru/TaN以及Cu/Ru/TaN薄膜，在高纯氮气保护下对样品进行快速热退火，用X射线衍射、四探针以及电流-时间测试等表征手段研究了Ru/TaN双层结构薄膜的热稳定性和对铜的扩散阻挡特性. 同时还对Ru/TaN结构上的铜进行了直接电镀. 实验结果表明Ru/TaN双层结构具有优良的热稳定性和扩散阻挡特性,在无籽晶铜互连工艺中有较好的应用前景.     

Physical and electrical characteristics of HfN gate electrode for advanced MOS devices

In this letter, the physical and electrical properties of physical vapor deposited (PVD) hafnium nitride (HfN) is studied for the first time as the metal gate electrode for advanced MOS devices applications. It is found that HfN possesses a midgap work function in tantalum nitride (TaN)/HfN/SiO/sub 2//Si MOS structures. TaN/HfN stacked metal-gated MOS capacitors exhibit negligible variations on equivalent oxide thickness (EOT), leakage current, and work function upon high-temperature treatments (up to 1000 /spl deg/C), demonstrating the excellent thermal stability of HfN metal gate on SiO/sub 2/. Our results suggest that HfN metal electrode is an ideal candidate for the fully depleted SOI and/or symmetric double gate MOS devices application.     

An electro-enhanced metalorganic chemical vapor deposition technique for producing thin copper films with (hfac)Cu(COD) as a precursor

A novel electro-enhanced metalorganic chemical vapor deposition (EEMOCVD) technique for producing copper (Cu) thin films on TaN/Si substrates with hexafluoroacetylacetonate-copper(I)-1,5-cyclo-octadine, (hfac)Cu^I(COD), as a precursor was investigated in this paper. This novel technique features supplying a direct current (DC) to TaN/Si substrates while the deposition of Cu thin films is in progress. Experiments on EEMOCVD yielded fortuitously positive results: (1) the deposited Cu films were superior in quality and (2) the growth rate of Cu film deposition increased. The above results are more desirable than those achieved through the conventional MOCVD (CMOCVD) technique. The proposed EEMOCVD technique hence proves to be more effective in forming smooth and continuous thin copper films.     

Self-aligned nickel, cobalt/tantalum nitride stacked-gate pMOSFETs fabricated with a low temperature process after metal electrode deposition

This letter reports the first replacement (Damascene) metal gate pMOSFETs fabricated with Ni/TaN, Co/TaN stacked electrode, where Ni or Co is in direct contact with the gate SiO/sub 2/, to adjust the electrode metal work function and TaN is used as the filling material for the gate electrode to avoid wet etching and CMP problems. The process is similar to the fabrication of traditional self-aligned polysilicon gate MOSFETs, except that in the back end (after the source/drain implants are activated) a few processing steps are added to replace the polysilicon with metal. Our data show that the Ni or Co/TaN gate electrode has the right work function for the pMOSFETs. The metal gate process can reduce the gate resistivity. Thermal stability of the stacked electrodes is studied and the result is reported in this paper. The damascene process flow bypasses high temperature steps (> 400/spl deg/C)critical for metal gate and hi k materials. This paper demonstrates that a low temperature anneal (300/spl deg/C) can improve the device performance. In this paper, the gate dielectrics is SiO/sub 2/.     

Backside copper metallization of GaAs MESFETs using TaN as thediffusion barrier

Backside copper metallization of GaAs MESFETs using TaN as the diffusion barrier was studied. A thin TaN layer of 40 nm was sputtered on the GaAs substrate before copper film metallization, as judged from the data of X-ray diffraction (XRD), Auger electron spectroscopy (AES), and cross-sectional transmission electron microscopy (TEM), the Cu/TaN films with GaAs were very stable without interfacial interaction up to 550°C annealing; the copper metallized MESFETs were thermally stressed at 300°C. The devices showed very little change in the device characteristics (<3%) after thermal stress, and the changes of the electrical parameters and RF characteristics of the devices after thermal stress were of the same order as those devices without Cu metallization, these results show that TaN is a good diffusion barrier for Cu in GaAs devices and the Cu/TaN films can be used for the backside copper metallization of GaAs MESFETs     

Some properties of inn films prepared by reactive evaporation

Some optical and electrical properties of degenerate InN films prepared by a reactive evaporation technique are presented. Thermal stability of these easily dissociated samples is discussed and evidence is presented indicating that the partial pressure of atomic nitrogen rather than diatomic nitrogen is a more fundamental parameter for describing thermal equilibrium. This has important implications for the growth of all group III-nitrides.     

CVD金刚石膜用作TaN2热敏打印头表面保护层的研究

报道了用微波等离子体化学气相淀积技术在ＴａＮ２电阻材料上淀积高质量金刚石薄膜的制备工艺，以及扫描电镜、Ｘ射线衍射、拉曼光谱、压痕测试的测试结果。探讨了提高金刚石膜在非金刚石衬底成核密度与粘附性的实验方法，从实验上证实了ＣＶＤ金刚石膜可以用作ＴａＮ２热敏打印头表面保护层。     

Effects in Surface Free Energy of Sputter-Deposited TaNx Films

TaNx thin films have attracted much attention for semiconductor integrated circuit (IC) packaging molding dies and forming tools due to their excellent hardness and thermal stability. Tantalum nitride (TaNx) thin films with TaN, TaN, TaN, TaN, and TaN were prepared using radio frequency (RF) sputter. The experimental results showed that the contact angle at 20 C go up with raising content to 119.2 at beginning, corresponding to TaN, and then drop off. In addition, the contact angle components decreased with increasing surface temperature. Because increasing surface temperature disrupts the hydrogen bonds between water and the films and water vaporize gradually. The total surface free energy (SFE) at 20 C decrease with content to raise to 39.6 mN/m(TaN) at the start, and then increase. A larger contact angle means a weaker hydrogen bonding, resulting in a lower SFE. The polar SFE component has same trend with total SFE, but the dispersive SFE component is on the contrary exactly. The polar SFE component is also lower than the dispersive SFE component. This results from hydrogen bonding being polar. The total SFE, dispersive SFE, and polar SFE of TaNx films decreased with increasing surface temperature. This is because water evaporation on the surface, disrupted hydrogen bonds, and surface entropy increase with increasing temperature. The film roughness has an obvious effect on the SFE and there is a tendency for the SFE to increase with increasing film surface roughness. SFE and surface roughness can be expressed as a function in direct ratio.     

Investigation on the atomic layer deposition of the Se doped Sb–Te phase change films using an alkyl-silyl precursor

We used TDMASb, Te(t-Bu)₂, and Se(SiMe₃)₂ as precursors to investigate the behavior of atomic vapor deposition (AVD) during formation of Se doped Sb–Te phase change films. The deposition was prepared by a sequential recipe for the atomic layer deposition (ALD) reaction with consideration of the electrostatic interactions between the Se alkyl-silyl precursor and the Sb and Te precursors. The Sb–Te–Se ternary films could be deposited by AVD at temperatures of 80–300 °C with fine controllability and high surface quality. The elemental composition of the films was controlled by varying the deposition temperature. The Se doping effect on the crystallization temperature and set resistance in the crystalline state was evaluated via electrical measurements and theoretical analyses by applying the glass transition temperature model and resonance bonding model. The results indicated that the incorporation of Se into Sb–Te films may provide for improved thermal stability and power consumption efficiency in phase-change random access memory (PCRAM) devices.     

Integrated vapor pressure, hygroswelling, and thermo-mechanical stress modeling of QFN package during reflow with interfacial fracture mechanics analysis

In this paper, a comprehensive and integrated package stress model is established for quad flat non-lead package with detailed considerations of effects of moisture diffusion, heat transfer, thermo-mechanical stress, hygro-mechanical stress and vapor pressure induced during reflow. The critical plastic materials, i.e., moldcompound and die attach are characterized for hygroswelling and moisture properties, which are not easily available from material suppliers. The moisture absorption during preconditioning at JEDEC Level 1, and moisture desorption at various high temperatures are characterized. The moisture diffusivity is a few orders higher at reflow temperature than moisture preconditioning temperature. Due to coefficient of moisture expansion mismatch among various materials, hygro-mechanical stress is induced. The concept is analogous to coefficient of thermal expansion mismatch which results in thermo-mechanical stress. Thermal diffusivity is much faster than the moisture diffusivity. During reflow, the internal package reaches uniform temperature within a few seconds. The vapor pressure can be calculated based on the local moisture concentration after preconditioning. Results show that the vapor pressure saturates much faster than the moisture diffusion, and a near uniform vapor pressure is reached in the package. The vapor pressure introduces additional strain of the same order as the thermal strain and hygrostrain to the package. Subsequently, the interfacial fracture mechanics model is applied to study the effect of crack length on die/mold compound and die/die attach delamination.     

Cu contact on NiSi/Si with thin Ru/TaN barrier

Thin Ru(5 nm)/TaN(15 nm) bi-layer was sputtered on the NiSi/Si substrate as a diffusion barrier in the copper contact structure. The barrier properties were investigated through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and electrical measurement. The whole Cu/Ru/TaN/NiSi/Si structure has a good thermal stability until after annealing at 450 °C. The Schottky barrier measurement shows that the leakage current increases after 450 °C annealing and after 500 °C annealing the barrier fails. Failure mechanism of the barrier stack is discussed.     

行波管夹持杆微波等离子体化学气相沉积金刚石厚膜改善散热性能研究

采用微波等离子体化学气相沉积法在行波管Al₂O₃夹持杆上沉积金刚石厚膜,取代传统有毒的氧化铍陶瓷杆,用于宽带大功率行波管改善其散热性能.经材料性能测试,慢波组件装配及性能测试,获得了较好的实验结果:导热率大于12W/cm.℃,介电常数为5.0~5.5,介质损耗为1×10^-3,体积电阻率大于10¹³Ω/cm; 慢波组件导热性能与同结构的BeO组件相比提高3.0倍.整管冷测参数全部合格;整管热测在C波段测得Po=95W,G=35db.     

LCP柔性基板的薄膜电阻制作技术

针对液晶聚合物(LCP)柔性基板高频电子封装应用需求,采用一种薄膜溅射工艺直接在LCP柔性基板上制作TaN薄膜电阻,研究不同等离子体预处理方式对LCP表面形貌和LCP表面薄膜金属膜层附着强度的影响,进一步研究溅射气压和氮气体积分数等参数对电阻性能的影响,考察LCP柔性基板上的TaN薄膜电阻精度及电阻温度系数(TCR),并制备出50Ω的薄膜电阻。结果表明:当射频功率为300 W的氧等离子体预处理600 s时,LCP表面的面粗糙度低,LCP基板表面薄膜金属膜层附着强度高,其值>5.0 N/mm²;当溅射功率为400 W、氮气体积分数为3%、溅射气压为0.2 Pa时,制备的TaN薄膜电阻的阻值精度高,阻值精度≤±4%,TCR电阻稳定性能好。     

Effects of group V precursor and step structure on ordering in GaInP

The effects of the P precursor have been studied for GaInP layers grown at 670°C on singular (001) GaAs substrates. Use of either of the two precursors, tertiarybutylphosphine (TBP) and phosphine (PH₃), for the organometallic vapor phase epitaxial growth, has been shown to result in the same degree of CuPt order in the epitaxial layers. However, the steps on the surface are mainly bilayers, approximately 5.8Å in height, for growth using TBP and mainly monolayers for growth using PH₃. This indicates that the step structure plays no role in the ordering process occurring on the surface during growth. Examination of the spacing between these surface steps vs the input partial pressure of the P precursor indicates that neither the surface diffusion coefficient nor the sticking coefficients of group III adatoms at the step edge is dependent on the P precursor. This suggests that the step structure also has no effect on the sticking coefficient.     

In Situ Thermolysis of a Ni Salt on Amorphous Carbon and Graphene Oxide Substrates

Understanding the thermal decomposition of metal salt precursors on carbon structures is essential for the controlled synthesis of metal-decorated carbon nanomaterials. Here, the thermolysis of a Ni precursor salt, NiCl₂·6H₂O, on amorphous carbon (a-C) and graphene oxide (GO) substrates is explored using in situ transmission electron microscopy. Thermal decomposition of NiCl₂·6H₂O on GO occurs at higher temperatures and slower kinetics than on a-C substrate. This is correlated to a higher activation barrier for Cl₂ removal calculated by the density functional theory, strong Ni-GO interaction, high-density oxygen functional groups, defects, and weak van der Waals using GO substrate. The thermolysis of NiCl₂·6H₂O proceeds via multistep decomposition stages into the formation of Ni nanoparticles with significant differences in their size and distribution depending on the substrate. Using GO substrates leads to nanoparticles with 500% smaller average sizes and higher thermal stability than a-C substrate. Ni nanoparticles showcase the fcc crystal structure, and no size effect on the stability of the crystal structure is observed. These findings demonstrate the significant role of carbon substrate on nanoparticle formation and growth during the thermolysis of carbon–metal heterostructures. This opens new venues to engineer stable, supported catalysts and new carbon-based sensors and filtering devices.     

Fermi-level pinning induced thermal instability in the effective work function of TaN in TaN/SiO/sub 2/ gate stack

In this letter, we demonstrate for the first time that the Fermi-level pinning caused by the formation of Ta(N)-Si bonds at the TaN/SiO/sub 2/ interface is responsible for the thermal instability of the effective work function of TaN in TaN/SiO/sub 2/ devices after high temperature rapid thermal annealing (RTA). Because of weak charge transfer between Hf and Ta(N) and hence negligible pinning effect at the TaN/HfO/sub 2/ interface, the effective work function of TaN is significantly more thermally stable on HfO/sub 2/ than on SiO/sub 2/ dielectric during RTA. This finding provides a guideline for the work function tuning and the integration of metal gate with high-/spl kappa/ dielectric for advanced CMOS devices.     

Thermally robust TaTb/sub x/N metal gate electrode for n-MOSFETs applications

In this letter, we study Terbium (Tb)-incorporated TaN (TaTb/sub x/N) as a thermally robust N-type metal gate electrode for the first time. The work function of the Ta/sub 0.94/Tb/sub 0.06/N/sub y/ metal gate is determined to be /spl sim/4.23 eV after rapid thermal anneal at 1000/spl deg/C for 30 s, and can be further tuned by varying the Tb concentration. Moreover, the TaTb/sub x/N-SiO/sub 2/ gate stack exhibits excellent thermal stability up to 1000/spl deg/C with no degradation to the equivalent oxide thickness, gate leakage, and time-dependent dielectric breakdown (TDDB) characteristics. These results suggest that Tb-incorporated TaN (TaTb/sub x/N) could be a promising metal gate candidate for n-MOSFET in a dual-metal gate Si CMOS process.