基于MIS电容器的Al2O3与In0.74Al0.26As的界面特性

采用In_0.74Al_0.26As/In_0.74Ga_0.26As/In_xAl_1-xAs异质结构多层半导体作为半导体层,制备了金属-绝缘体-半导体（MIS）电容器。其中,SiN_x和SiN_x/Al₂O₃分别作为MIS电容器的绝缘层。高分辨率透射电子显微镜和X射线光电子能谱的测试结果表明,与通过电感耦合等离子体化学气相沉积生长的SiN_x相比,通过原子层沉积生长的Al2_O3可以有效地抑制Al₂O₃和In_0.74Al_0.26As界面的In₂O₃的含量。根据MIS电容器的电容-电压测量结果,计算得到SiN_x/Al₂O₃/In...     

原子层沉积方法制备低温多层Al2O3/TiO2复合封装薄膜的研究

原子层沉积(ALD)方法可以制备出高质量薄膜,被认为是可应用于柔性有机电致发光器件(OLED)最有发展前景的薄膜封装技术之一。本文采用原子层沉积(ALD)技术,在低温(80℃)下,研究了Al₂O₃及TiO₂薄膜的生长规律,通过钙膜水汽透过率(WVTR)、薄膜接触角测试等手段,研究了不同堆叠结构的多层Al₂O₃/TiO₂复合封装薄膜的水汽阻隔特性,其中5 nm/5 nm×8 dyads(重复堆叠次数)的Al₂O₃/TiO₂叠层结构薄膜的WVTR达到2.1×10^-5 g/m²/day。采用优化后的Al₂O₃/TiO₂叠层结构薄膜对OLED器件进行封装,实验发现封装后的OLED器件在高温高湿条件下展现了较好的寿命特性。     

B2O3对BaZrO3微波介质陶瓷材料性能的影响

以分析纯的BaCO₃、ZrO₂、B₂O₃为原料,采用传统固相法制备了添加x%B₂O₃(质量分数x=0.5～5.0)的BaZrO₃微波介质陶瓷。运用扫描电子显微镜、矢量网络分析仪和X线衍射仪等实验手段研究了不同B₂O₃添加量对BaZrO₃陶瓷微观结构、相组成及微波介电性能的影响。结果表明,随着B₂O₃添加量的增加,材料致密烧结温度降低,介电常数减小,介电损耗降低。当B₂O₃添加量超过1%时,有BaZr(BO₃)₂相析出。在B₂O₃添加量为3%,烧结温度为1 300℃时,BaZrO₃陶瓷获得优异的微波介电性能：介电常数ε_r=33.02,品质因数与频率之积Q×...     

95%Al2O3陶瓷Mo-Mn金属化层烧结机理研究

通过对95%Al2O3陶瓷Mo-Mn金属化层烧结前后显微结构的分析,对不同Mo含量金属化配方的块状烧结体及高纯高致密Al2O3陶瓷表面金属化层显微结构的研究,探讨了95%Al2O3陶瓷Mo-Mn金属化层的烧结过程,揭示了Mo骨架结构中Mo颗粒间气孔形成的机理.     

稀土氧化物对Al2O3-ZrO2激光熔覆层组织与性能影响研究

为了解决在钛合金表面通过激光熔覆技术制备得到的Al₂O₃-ZrO₂陶瓷涂层脆性大、易开裂的问题,有效提升钛合金性能,扩大其使用范围,采取在熔覆层材料中添加稀土氧化物CeO2的方法,对Al₂O₃-ZrO₂陶瓷熔覆层的裂纹敏感性进行了改善。通过分析熔覆层宏观、微观组织,测试熔覆层性能,研究CeO2含量对熔覆层裂纹敏感性的影响规律,探究CeO₂调控辅助激光熔覆制备Al₂O₃-ZrO₂陶瓷涂层最佳含量,揭示稀土氧化物对熔覆层裂纹敏感性影响的作用机理。结果表明：通过添加稀土氧化物调控,熔覆层裂纹数量明显减少,熔覆层裂纹控制主要归功于稀土元素对熔覆层组织的细晶强化效应;当CeO₂质量分数为0.8%时,熔覆层微观组织最为致密,对裂纹抑制作用最为明显;熔覆层断裂韧性相较未添加稀土调控辅助时有明显提高,从4.1 MPa·m^1/2提高至7.3 M...     

水辅助激光无重铸层钻孔Al2O3陶瓷实验研究

为了解决传统加工过程中重铸层无法消除的问题，采用超快皮秒激光创新性地在水介质中对Al₂O₃陶瓷进行皮秒激光钻孔实验，并与空气中钻孔结果进行对比，研究了皮秒激光主要参量如单脉冲能量、扫描次数等对陶瓷微孔的孔径、锥度和重铸层厚度的影响规律，并分析讨论不同介质中皮秒激光与Al₂O₃陶瓷相互作用机理及材料去除机制。结果表明，在水介质中激光钻孔直径增加约35μm、微孔锥度降低至1.04°并可获得无重铸层钻孔效果；激光作用过程中水的存在会引起空泡作用、吸收作用和运输作用，有效防止了去蚀材料二次黏附，消除了重铸层和降低了微孔锥度，提升了微孔质量。该研究阐述了水辅助激光钻孔的具体影响状况并加深了对水辅助的影响机理理解。     

Al2O3-SiO2/纤维素复合气凝胶的制备及其阻燃性能

针对纤维素气凝胶隔热性能差、易燃烧等问题,基于液氮定向冷冻及真空冷冻干燥技术,以低成本、环境友好的微晶纤维素为原材料,Al₂O₃-SiO₂溶胶为阻燃剂,去离子水为溶剂,加入硼酸作为催化剂控制共水解进程,制备出隔热阻燃性能良好的Al₂O₃-SiO₂/纤维素复合气凝胶。采用扫描电子显微镜、傅里叶变换红外光谱仪、热重分析仪、锥形量热仪等研究了Al₂O₃-SiO₂溶胶含量对材料结构与性能的影响,并分析了复合气凝胶的阻燃机制。结果表明,随着Al₂O₃-SiO₂溶胶含量的增加,Al₂O₃-SiO₂/纤维素复合气凝胶从蜂窝状结构向多孔三维网络结构转变,孔径减小。Al₂O₃-SiO₂溶胶与微晶纤维素溶液体积比为2...     

纯Mo法Al_2O_3瓷和金属的封接

所谓Mo-Mn法和纯Mo法是通过金属化、镀Ni和其后硬焊而形成的陶瓷和金属气密封接的方法.关于Mo-Mn法Al~2O~3瓷和金属的封接,作者在以前的文章中业已报导。本文所研究的是用含MnO的92%Al~2O~3的圆片,以纯Mo法对可伐另件进行了封接。并研究了封接层的抗张强度和封接件的真空气密性. 用光学显微镜和电子扫描显微镜以及电子探针对封接层进行了检验. 为了解纯Mo法的封接机理,石英玻璃和Mo箔的封接也附带地进行了观察。本文所得的结果如下: (1)当1400-1400℃/60分进行陶瓷金属化时,获得了最高的封接强度和最好的真空气密性。 (2)封接处是按下列顺序的多层所组成:陶瓷-金属化层-镀Ni层-硬焊料层-镀Ni层-可伐。在Mo-Mn法的封接中,看到了陶瓷和金属化层之间的中间层。而在纯Mo法中,则认为是不存在的. (3)在石英玻璃-Mo箔封接中,Mo金属表面层被氧化,如此形成的Mo氧化物扩散到石英玻璃中而形成了过渡层,从而十分有利地降低封接应力和改善粘结 (4)SiO~2-MnO-Al~2O~3系统玻璃相和Ni填充了Mo金属化层的孔隙;前者来自于陶瓷体,而后者来自于镀Ni层。这些物质的浸润和相互扩散得到了强固的和真空气密的封接层。     

Bi2O3掺杂Ba0.85Ca0.15(Zr0.1Ti0.88Mn0.02)O3压电陶瓷及微型气泵的制备与性能研究

采用固相法制备了Bi₂O₃掺杂的Ba_0.85Ca_0.15(Zr_0.1Ti_0.88Mn_0.02)O₃压电陶瓷，研究了体系的微观结构，以及Bi₂O₃掺杂量对体系压电性能的影响；将体系最优性能的样品装配成微型气泵，并与日本村田的MZB1001T02微型泵进行了性能对比。研究表明，Bi₂O₃掺杂Ba_0.85Ca_0.15(Zr_0.1Ti_0.88Mn_0.02)O₃的无铅压电陶瓷呈单一的钙钛矿结构，少量的Bi₂O₃掺杂使体系保持了三方-四方相共存的特性。当掺杂量(质量分数)为0.05%时，样品晶粒分布均匀，介电和压电性能最优，即ε^T_33...     

氧化铝陶瓷的低温钼金属化研究

采用BaO-Al2O3-SiO2（BAS）微晶玻璃的母体玻璃作为烧结助剂,在氧化铝陶瓷表面低温烧结Mo金属化层。研究了金属化烧结温度及BAS含量对样品抗拉强度的影响,讨论了金属化机理。结果表明：以BAS微晶玻璃的母体玻璃作为烧结助剂,可在1500~1550℃烧成Mo金属化层,金属化层致密,连接样品的抗拉强度大于260 MPa。     

Good High-Temperature Stability of TiN/ Al2O3/WN/TiN Capacitors

For the first time, good thermal stability up to an annealing temperature of 1000degC has been demonstrated for a new TiN/Al₂O₃/WN/TiN capacitor structure. Good electrical performance has been achieved for the proposed layer structure, including a high dielectric constant of ~ 10, low leakage current of 1.2times10^-7 A/cm² at 1 V, and excellent reliability. A thin WN layer was incorporated into the metal-insulator-metal capacitor between the bottom TiN electrode and the Al₂O₃ dielectric suppressing of interfacial-layer formation at Al₂ O₃/TiN interfaces and resulting in a smoother Al₂O₃/TiN interface. This new layer structure is very attractive for deep-trench capacitor applications in DRAM technologies beyond 50 nm.     

Low-frequency noise in Si0.7Ge0.3 surface channel pMOSFETs with ALD HfO2/Al2O3 gate dielectrics

Low-frequency noise was characterized in Si_0.7Ge_0.3 surface channel pMOSFETs with ALD Al₂O₃/HfO₂/Al₂O₃ stacks as gate dielectrics. The influences of surface treatment prior to ALD processing and thickness of the Al₂O₃ layer at the channel interface were investigated. The noise was of the 1/f type and could be modeled as a sum of a Hooge mobility fluctuation noise component and a number fluctuation noise component. Mobility fluctuation noise dominated the 1/f noise in strong inversion, but the number fluctuation noise component, mainly originating from traps in HfO₂, also contributed closer to threshold and in weak inversion. The number fluctuation noise component was negligibly small in a device with a 2 nm thick Al₂O₃ layer at the SiGe channel interface, which reduced the average 1/f noise by a factor of two and decreased the device-to-device variations.     

Improved gain performance in Yb3+-sensitized Er3+-doped alumina (Al2O3) channel opticalwaveguide amplifiers

Small-signal amplification in short, Yb³⁺-sensitized, Er³⁺-doped alumina (Al₂O₃) channel optical waveguides with high Er³⁺ concentrations is analyzed. Taking into account uniform up conversion, excited state absorption (ESA) from the Er³⁺ metastable level (⁴I_13/2 ), and Yb³⁺→Er³⁺ energy transfer by cross relaxation, the obtainable gain improvements compared to Yb³⁺ -free Er³⁺-doped Al₂O₃ optical waveguides are investigated. The amplifier model is based on propagation and population rate equations and is solved numerically by combining finite elements and the Runge-Kutta algorithm. The analysis predicts that 5-cm long Yb³⁺/Er³⁺ co-doped Al₂O ₃ waveguides show 13-dB net signal gain for 100 mW pump power at λ_p=980 nm     

High-performance polycrystalline SiGe thin-film transistors usingAl2O3 gate insulators

The use of aluminum oxide as the gate insulator for low temperature (600°C) polycrystalline SiGe thin-film transistors (TFTs) has been studied. The aluminum oxide was sputtered from a pure aluminum target using a reactive N₂O plasma. The composition of the deposited aluminum oxide was found to be almost stoichiometric (i.e., Al₂O₃), with a very small fraction of nitrogen incorporation. Even without any hydrogen passivation, good TFT performance was measured an devices with 50-nm-thick Al₂O₃ gate dielectric layers. Typically, a field effect mobility of 47 cm²/Vs, a threshold voltage of 3 V, a subthreshold slope of 0.44 V/decade, and an on/off ratio above 3×10⁵ at a drain voltage of 0.1 V can be obtained. These results indicate that the direct interface between the Al₂ O₃ and the SiGe channel layer is sufficiently passivated to make Al₂O₃ a better alternative to grown or deposited SiO₂ for SiGe field effect devices     

Semiconductor lasers with 2-D-photonic crystal mirrors based on awet-oxidized Al2O3-mask

We have fabricated and investigated AlGaAs-InGaAs-based ridge waveguide (RWG) lasers with two-dimensional (2-D) triangular photonic crystal (PC) mirrors using a wet-oxidized Al₂O₃ mask for the dry etching of the PC at one end of the ridge. The laser structure includes a 60-nm-thick AlAs layer positioned in the upper cladding, which is converted into Al₂O₃ after the definition of the PC by electron beam lithography and shallow etching. Etching of the holes is then continued using the Al₂O₃ mask, to a final depth of 600 nm. The continuous-wave characteristics of the lasers show a clear dependence on the period of the PC including a significant decrease of the threshold current and an increase of the efficiency for properly adjusted crystal parameters     

Nd:Y2O3透明陶瓷4F3/2-4I11/2跃迁光谱及高效激光输出

报道了采用真空烧结法结合热等静压技术制备的Nd:Y₂O₃透明陶瓷的荧光光谱特性及相关激光输出。通过与Nd:YAG透明陶瓷的荧光光谱对比,表明Nd:Y₂O₃透明陶瓷的4F_3/2-4I_11/2跃迁光谱存在着多个增益相当的谱线,这更有利于实现同时双波长段激光振荡;不同斯塔克子跃迁光谱的离散特性有利于通过腔镜镀膜控制不同波长损耗,获得丰富的1.0~1.1 μm波段激光。利用简单的平平两镜腔结构完成进一步的实验,通过选择的输出镜片镀膜获得了输出功率3.62 W、转换效率40.4%的1074.6 nm和1078.8 nm的双波长输出和输出功率1.7 W、转换效率19.4%的1130.3 nm波长输出。     

High-density MIM capacitors using Al2O3 andAlTiOx dielectrics

We have investigated the electrical characteristics of Al₂ O₃ and AlTiO_x MIM capacitors from the IF (100 KHz) to RF (20 GHz) frequency range. Record high capacitance density of 0.5 and 1.0 μF/cm² are obtained for Al₂ O₃ and AlTiO_x MIM capacitors, respectively, and the fabrication process is compatible to existing VLSI backend integration. However, the AlTiO_x MIM capacitor has very large capacitance reduction at increasing frequencies. In contrast, good device integrity has been obtained for the Al₂O₃ MIM capacitor as evidenced from the small frequency dependence, low leakage current, good reliability, small temperature coefficient, and low loss tangent     

Electrical characterization of Al2O3n-channel MOSFETs with aluminum gates

High-effective mobilities are demonstrated in Al₂O₃ based n-channel MOSFETs with Al gates. The Al₂O₃ was grown in ultra-high vacuum using a reactive atomic beam deposition system. The mobility with maximum values at approximately 270 cm²/Vs, is found to approach that of SiO ₂ based MOSFETs at higher fields