电子束共蒸发Al2O3-La2O3和ZrO2-Ta2O5复合薄膜的介电性能研究

Al2O3、ZrO2、Ta2O5和La2O3薄膜在栅介质、无机EL介质和光学薄膜方面有着重要用途,但对其复合薄膜介电性能方面的研究很少。文章采用电子束共蒸发法制备了厚度分别为414nm和143nm的Al2O3-La2O3（ALO）和ZrO2-Ta2O5（ZTO）复合薄膜,用Sawyer—Tower电路测得介电常数分别为17和34,反映介电损耗的参数△Vy分别为0．013V和0．56V,击穿场强分别为128MV／m和175MV／m,在50MV／m场强下,ALO的正、反向漏电流密度分别为3．1×10-5／cm2和4．1×10-5A／cm2,ZTO的正、反向漏电流密度分别为3．9×10-5／cm2和3．7×10-5A／cm2。另外,实验还与电子束蒸发和反应溅射制备的Al2O3、ZrO2、Ta2O5的介电性能做了比较,结果表明,上述复合薄膜单独作为无机EL绝缘层是不合适的。     

Ruby (Al2O3: Cr3+) Fluorescence Thermometer Using PLD-PMSR Technique

A kind of fluorescence fiber-optic thermometer is devised based on the solid-state ruby fluorescence material. The characteristics of fluorescence material absorption and emission are analyzed, and the fiber-optic temperature measurement probe in ruby is developed. This system is particularly adaptable to the temperature measurement in the range of 20 ℃ to 600 ℃. During the experiment, this method is proved to be useful to temperature measurement with high resolution and precision.     

Ruby (Al_2O_3∶Cr~(3+)) Fluorescence Thermometer Using PLD-PMSR Technique

A kind of fluorescence fiber-optic thermometer is devised based on the solid-state ruby fluorescence material. The characteristics of fluorescence material absorption and emission are analyzed, and the fiber-optic temperature measurement probe in ruby is developed. This system is particularly adaptable to the temperature measurement in the range of 20℃ to 600℃. During the experiment, this method is proved to be useful to temperature measurement with high resolution and precision.     

Electrical behavior of ZrO2-MgO-Y2O3 solid electrolyte

ZrO₂ doped with various compositions of two stabilizers, Y₂O₃ and MgO, in order to lower sintering temperature and improve the electrical behavior of sintered bodies have been investigated in this study. The results show that densification of Y₂O₃-ZrO₂ system is enhanced by MgO addition. Sintered bodies display a bimodal distribution of grains under proper addition. This research discovers that (YO_1.5)_0.08(MgO)_0.04(ZrO₂)_0.88 system has high conductivity and responsible oxygen sensitivity. With regard to oxygen sensitivity, the log behavior EMF takes place at 440 and 550° C. Besides, the EMF decreases at a very low oxygen pressure caused by electronic conduction and electrode polarization.     

ZrO2 insulator modified by a thin Al2O3 film to enhance the performance of InGaZnO thin-film transistor

A high-performance InGaZnO (IGZO) thin-film transistor (TFT) with ZrO₂–Al₂O₃ bilayer gate insulator is fabricated. Compared to IGZO-TFT with ZrO₂ single gate insulator, its electrical characteristics are significantly improved, specifically, enhancement of I_on/I_off ratios by one order of magnitude, increase of the field-effect mobility (from 9.8 to 14 cm²/Vs), reduction of the subthreshold swing from 0.46 to 0.33 V/dec, the maximum density of surface states at the channel-insulator interface decreased from 4.3 × 10¹² to 2.5 × 10¹² cm⁻². The performance enhancements are attributed to the suppression of leakage current, smoother surface morphology, and suppression of charge trapping by using Al₂O₃ films to modify the high-k ZrO₂ dielectric.     

Model based precise analysis of the injection currents in Al/ZrO2/Al2O3/ZrO2/SiO2/Si structures for use in charge trapping non-volatile memory devices

Metal/insulator/Silicon (MIS) capacitors containing multilayered ZrO₂/Al₂O₃/ZrO₂/SiO₂ dielectric were investigated in order to evaluate the possibility of their application in charge trapping non-volatile memory devices. The ZrO₂/Al₂O₃/ZrO₂ stacks were deposited by reactive rf magnetron sputtering on 2.4 nm thick SiO₂ thermally grown on p-type Si substrate. C–V characteristics at room temperature and I–V characteristics recorded at temperatures ranging from 297 K to 393 K were analyzed by a comprehensive model previously developed. It has been found that Poole-Frenkel conduction in ZrO₂ layers occurs via traps energetically located at 0.86 eV and 1.39 eV below the bottom of the conduction band. These levels are identified as the first two oxygen vacancies related levels in ZrO₂, closest to its conduction band edge, whose theoretical values reported in literature are: 0.80 eV, for fourfold, and 1.23 eV, for threefold coordinated oxygen vacancies.     

钙铝硼硅玻璃/氧化铝复合材料性能研究

通过高温熔融法制备的CaO-Al2O3-B2O3-SiO2玻璃粉末与α-Al2O3粉末按照质量分数50:50混合,烧结制备了钙铝硼硅玻璃/氧化铝系低温共烧陶瓷材料,研究了烧结温度对复合材料的物相组成、微观结构、力学性能及介电性能的影响.结果表明,875℃烧结制备的复合材料性能最佳,抗弯强度为164 MPa,介电常数为7.8,介电损耗为0.001 3,热膨胀系数为5.7×10-6/℃,具有良好的综合性能,可用作低温共烧陶瓷基板材料.     

Memory characteristics of Al2O3/La2O3/Al2O3 multi-layer films with various blocking and tunnel oxide thicknesses

In order to investigate charge trap characteristics with various thicknesses of blocking and tunnel oxide for application to non-volatile memory devices, we fabricated 5 and 15 nm Al₂O₃/5 nm La₂O₃/5 nm Al₂O₃ and 15 nm Al₂O₃/5 nm La₂O₃/5, 7.5, and 10 nm Al₂O₃ multi-stack films, respectively. The optimized structure was 15 nm Al₂O₃ blocking oxide/5 nm La₂O₃ trap layer/5 nm Al₂O₃ tunnel oxide film. The maximum memory window of this film of about 1.12 V was observed at 11 V for 10 ms in program mode and at ?13 V for 100 ms in erase mode. At these program/erase conditions, the threshold voltage of the 15 nm Al₂O₃/5 nm La₂O₃/5 nm Al₂O₃ film did not change for up to about 10⁴ cycles. Although the value of the memory window in this structure was not large, it is thought that a memory window of 1.12 V is acceptable in the flash memory devices due to a recently improved sense amplifier.     

高分辨飞秒光学相干断层成像系统

建立了飞秒激光自由空间光学相干断层成像OCT)系统,给出了该系统的初步实验结果。系统的光源为掺Ti蓝宝石锁模激光器,输出脉宽小于50fs,中心波长为800nm,谱宽约为40nm,飞秒OCT所达到的纵向分辨率为8μm,横向分辨率为7．6μm,并用于飞秒激光微加工样品表面轮廓的检测。     

fmax为30.8GHz的超薄Al2O3绝缘栅GaN MOS-HEMT器件

报道了一种利用原子层淀积(ALD)生长超薄(3.5nm)Al2O3为栅介质的高性能AlGaN/GaN金属氧化物半导体高电子迁移率晶体管(MOS-HEMT).新型AlGaN/GaN MOS-HEMT器件栅长1μm,栅宽120μm,栅压为+3.0V时最大饱和输出电流达到720mA/mm,最大跨导达到130mS/mm,开启电压保持在-5.0V,特征频率和最高振荡频率分别为10.1和30.8GHz.     

fmax为30.8GHz的超薄Al2O3绝缘栅GaN MOS-HEMT器件

报道了一种利用原子层淀积(ALD)生长超薄(3.5nm)Al2O3为栅介质的高性能AlGaN/GaN金属氧化物半导体高电子迁移率晶体管(MOS-HEMT).新型AlGaN/GaN MOS-HEMT器件栅长1μm,栅宽120μm,栅压为 3.0V时最大饱和输出电流达到720mA/mm,最大跨导达到130mS/mm,开启电压保持在-5.0V,特征频率和最高振荡频率分别为10.1和30.8GHz.     

DNA Sensing Using Nanocrystalline Surface‐Enhanced Al2O3 Nanopore Sensors

A new solid‐state, Al₂O₃ nanopore sensor with enhanced surface properties for the real‐time detection and analysis of individual DNA molecules is reported. Nanopore formation using electron‐beam‐based decomposition transforms the local nanostructure and morphology of the pore from an amorphous, stoichiometric structure (O to Al ratio of 1.5) to a heterophase crystalline network, deficient in O (O to Al ratio of ≈0.6). Direct metallization of the pore region is observed during irradiation, thereby permitting the potential fabrication of nanoscale metallic contacts in the pore region with application to nanopore‐based DNA sequencing. Dose‐dependent phase transformations to purely γ and/or α‐phase nanocrystallites are also observed during pore formation, allowing for surface‐charge engineering at the nanopore/fluid interface. DNA transport studies reveal an order‐of‐magnitude reduction in translocation velocities relative to alternate solid‐state architectures, accredited to high surface‐charge density and the nucleation of charged nanocrystalline domains. The unique surface properties of Al₂O₃ nanopore sensors make them ideal for the detection and analysis of single‐stranded DNA, double‐stranded DNA, RNA secondary structures, and small proteins. These nanoscale sensors may also serve as useful tools in studying the mechanisms driving biological processes including DNA–protein interactions and enzyme activity at the single‐molecule level.     

Bi2O3对Al2O3-ZnO-Bi2O3-B2O3低熔玻璃结构和性能的影响

采用传统的熔淬技术制得了低熔Al2O3-ZnO-Bi2O3-B2O3玻璃,研究了玻璃结构、玻璃特征温度、线膨胀系数(α1)以及密度随Bi2O3含量的变化关系.结果表明:随着Bi2O3含量的增加,玻璃网络中[BO4]取代了部分[BO3],玻璃网络中出现Bi-O结构,玻璃中非桥氧的数量也逐渐增多;软化温度(ts)、玻璃化温度(tg)都是先上升后下降,而线膨胀系数先减小后逐渐增大,玻璃密度先是线性增加,然后增加趋势变大.     

原位XPS分析Al2O3作为势垒层的Er2O3/Si结构

在超高真空条件下,通过脉冲激光沉积(PLD)技术制作了Er2O3/Al2O3/Si多层薄膜结构,原位条件下利用X射线光电子能谱(XPS)研究了Al2O3作为势垒层的Er2O3与Si界面的电子结构.XPS结果表明,Al2O3中Al的2p芯能级峰在低、高温退火前后没有变化;Er的4d芯能级峰来自于硅酸铒中的铒,并非全是本征氧化铒薄膜中的铒;衬底硅的芯能级峰在沉积Al2O 3时没有变化,说明Al2O3薄膜从沉积到退火不参与任何反应,与Si界面很稳定;在沉积Er2O3薄膜和退火过程中,有硅化物生成,表明Er2O3与Si的界面不太稳定,但随着Al2O3薄膜厚度的增加,其硅化物中硅的峰强减弱,含量减少,说明势垒层很好地起到了阻挡扩散的作用.     

Al2O3/Al复合材料界面上MgAl2O4尖晶石形成的高分辨电镜观察

界面问题一直是复合材料研究者最关心的话题之一.界面结合的好坏直接关系到载荷从基体向增强体的传递效率.Al2O3/Al复合材料中,由于Al与Al2O3本征不润湿的特征,人们提出了一系列的措施来改良界面,其中一种就是基体合金化.Mg元素是显著增强润湿的合金元素之一,但是由于Mg在界面上引起的一系列化学反应使其界面反应润湿现象变得复杂起来.     

纳米晶ZrO2-Al2O3:Dy3+的制备及发光性质的研究

为了研究纳米晶ZrO2-Al2O3:Dy3+的晶相变化、发光特性及ZrO2-Al2O3与Dy3+之间是否有能量传递,采用化学共沉淀法制备了纳米晶ZrO2-Al2O3:Dy3+复合粉体。用X射线衍射图对粉体进行表征。随着煅烧温度的增加,粉末的晶相发生变化。通过对粉体晶相的分析可知,ZrO2和Al2O3在1100℃至1200℃时固溶,在1300℃时有一小部分固溶。用353nm的波长激发基质,从发射光谱中看到Dy3+丰富的发射能级,其发射光谱的主发射峰在483nm和583nm处,以483nm为激发波长得到激发光谱。结果表明,由于激发光谱中包含了来自于对基质的吸收,基质ZrO2-Al2O3和Dy3+之间存在能量传递。     

Al2O3高k栅介质的可靠性

利用反应溅射方法制备了等效氧化层厚度为3.45nm的Al2O3栅介质MOS电容,研究了Al2O3作为栅介质的瞬时击穿和恒压应力下的时变击穿等可靠性特征.击穿实验显示,样品的Al2O3栅介质的等效击穿场强大小为12.8MV/cm.在时变击穿的实验中,Al2O3栅介质表现出类似于SiO2的软击穿现象.不同栅压应力作用的测试结果表明,介质中注入电荷的积累效应是引起软击穿的主要因素,其对应的介质击穿电荷QBD约为30～60C/cm2.     

99Al2O3陶瓷的烧成工艺

以两种结构的99Al2O3陶瓷的烧成为例,研究了烧成工艺对烧成结果的影响,分析了99Al2O3陶瓷烧成时开裂的原因,并提出了有效的解决方案.     

Al2O3高k栅介质的可靠性

利用反应溅射方法制备了等效氧化层厚度为3．45nm的Al2O3栅介质MOS电容，研究了Al2O3作为栅介质的瞬时击穿和恒压应力下的时变击穿等可靠性特征．击穿实验显示，样品的Al2O3栅介质的等效击穿场强大小为12.8MV／cm.在时变击穿的实验中，Al2O3栅介质表现出类似于SiO2的软击穿现象．不同栅压应力作用的测试结果表明，介质中注入电荷的积累效应是引起软击穿的主要因素，其对应的介质击穿电荷QBD约为30～60C／cm^2．