Moire/spl acute/ minimization condition in three-dimensional image displays

A moire/spl acute/ minimization condition is found analytically for the contact-type three-dimensional (3-D) imaging systems by approximating 3-D displays as four superposed sine gratings. Finding maximization conditions for two-dimensional (2-D) waves in this structure provides minimization of moire/spl acute/s. The global extremum was found at a certain angle which does not depend on the period. Experiments confirm the analytical findings. Practical advantage of using that angle is in its wide areas of applications: 3-D displays can be made to have almost invisible moire/spl acute/s with using this angle without regards to other specific parameters like pixel size and pitch of the screen.     

Sensitive strain measurements of bonded SOI films using Moire/spl acute/

The authors have developed a simple technique to quantify strain in bonded Si films and used it to compare the strain induced by two distinct wafer bonding methods. This method consists of patterning sets of moire/spl acute/ gratings on silicon-on-insulator (SOI) substrates prior to bonding using a G-line stepper. After planarization, bonding, and etch-back, the same lithography step is performed on the flipped patterns. The resultant interference between upper and lower gratings produces moire/spl acute/ fringes which is a measure of the strain. In the experiments, the sensitivity of the measurement is approximately 20 nm. This approach has been used to compare two methods of wafer bonding. The first method, a manual bonding technique, yielded strain of up to 100 nm/mm. The second method employed a commercial-grade bonder and resulted in film strains below 40 nm/mm. In the bonding schemes the authors have studied, they believe strain results mainly from induced wafer bow during bonding and stress contributions of deposited films. This scheme was developed to address wafer strain that arises from a direct-alignment double-gate MOSFET fabrication scheme (Meinhold, 1994).     

薄膜应力激光测量的新装置

介绍了一种基于多光束原理的薄膜应力测试方法,通过对反射光光点间距变化的检测,可以实时得到应力的信息。其灵敏度优于2.5×106 Pa,精度优于5%。该方案具有结构简单、测量速度快、适应性强等特点,与计算机自动控制系统相结合,可以应用于生产线的薄膜生长过程控制检测。     

Ramped current stress for fast and reliable wafer level reliability monitoring of thin gate oxide reliability

A ramped dielectric stress measurement, suitable for fast wafer level reliability (fWLR) monitoring, is assessed for thin gate oxide thicknesses down to 2.2 nm. Severe difficulties usually occur for the reliable detection of soft/hard breakdown in a short time interval and due to high direct tunneling currents. These are discussed and an exponentially ramped current stress is introduced tackling the problems. Early oxide fails were covered by a fast voltage ramp carried out before the current ramp. The advantages of the method are highlighted which has already been implemented for fWLR monitoring in high volume production on scribe line structures.     

磁控溅射制备Zr膜的应力研究

为了研究磁控溅射方法制备的Zr膜的应力分布情况,采用探针轮廓仪测量镀膜前后基片在1维方向上的形变,根据镀膜前后基片曲率半径的变化和Stoney公式,用自编应力计算软件计算出薄膜的内应力。结果表明,Zr膜中主要存在的是压应力,且分布不均匀;工作气压对Zr膜内应力影响不大,但膜厚对Zr膜内应力影响较大,且随膜厚的增加,Zr膜中压应力减小。     

Electrooptic temperature sensor based on a Fabry-Pe/spl acute/rot resonator with a liquid crystal film

An electrooptic (EO) temperature sensor based on a Fabry-Pe/spl acute/rot (FP) resonator with a nematic liquid crystal (NLC) film is proposed. A novel compensation scheme of the EO effect allows for precise determination of temperature by monitoring the resonant wavelength of the NLC FP sensor. The proposed EO temperature sensor provides good stability, high resolution, self-calibration capability, and low driving voltage.     

A study on the variation of effective CTE of printed circuit boards through a validated comparison between strain gages and Moire/spl acute/ interferometry

The effective coefficient of thermal expansion (CTE) of printed circuit boards (PCBs) have a great deal of influence on the reliability of solder joints in microelectronic packages. In this paper we carryout a systematic characterization of nineteen circuit board samples using strain gages, further validated by moire/spl acute/ interferometry, to understand the impact of CTE variation on the reliability of solder joints. It is shown that the measured effective coefficient of thermal expansion varied in a wide range by as much as 5 PPM about the commonly used value of 17 PPM. This is shown to cause a significant reliability impact for a representative plastic ball grid array package assembly. The comparison between strain gage and moire/spl acute/ interferometry showed good overall correlation, but differed from each other by as much as 2.73 parts per million (PPM). The possible sources of error in each technique are identified and discussed.     

S-on-1测量方式下薄膜激光损伤的累积效应

为了研究薄膜激光损伤机理及影响因素,基于平顶光束辐照测量的原理,采用1064nm的Nd:YAG激光器,对电子束热蒸发方式镀制的HfO₂薄膜在重复频率激光作用下损伤的累积效应进行了理论分析和实验验证。运用损伤阈值的测量原理,分析了1-on-1和S-on-1两种测量方式的特点,并分别开展了测量实验。采用二分法查找辐照激光能量,每个能量密度辐照20个测试点,应用零几率损伤阈值和最小二乘法拟合确定测量结果。结果表明,对同种薄膜,1-on-1测量方式测得的损伤阈值为15.75J/cm2,S-on-1测量方式测得的损伤阈值为11.90J/cm2;从损伤阈值与损伤形貌两方面的对比表明,S-on-1测量方式体现了典型的累积效应。此结果对深入研究薄膜激光损伤的机理和影响因素具有重要意义。     

An assessment of change in stress due to cross-sectioning in moire/spl acute/ interferometric characterization of electronic packages

Cross-sectional moire/spl acute/ interferometry technique is a very commonly applied one for the characterization of electronic packages. While the technique is popular, its use has not been accompanied by rigorous evaluation of its measurement accuracy. Such an evaluation, necessary because the cross-sectioning destructively modifies the original geometry, is the goal of the current paper. In the present study, a five-layer specimen with intact axi-symmetry as well as one in which the symmetry is destroyed through cross-sectioning are chosen as the vehicles for developing an understanding of the effect of cross-sectioning. We present a rigorous validation of an analytical elasticity model of axi-symmetric package-like structures in which the model prediction is shown to be accurate to within 1% of experimental measurement. The validated analytical model is used to estimate a reduction in radial stress of approximately 40% due to the cross-sectioning of the circular specimens, while the radial strains were virtually unaffected by cross-sectioning. These results suggest that cross-sectional moire/spl acute/ interferometry is likely to yield accurate strains, but not stresses. Since damage under cyclic loading is a function of both stress and strain, the use of moire/spl acute/ interferometry for studying the evolution of strains in packages under cyclic loading is likely to be grossly in error.     

Deposition of GaN thin film on ZnO/Si by DIBD method

The GaNis a semiconductor material witha widefor-bidden band(Eg=3.36eV).It has many unique advan-tages such as high electron drift velocity,small dielectricconstant,goodthermal conduction et al.It is a favorablematerial for making electric devices with hi…     

Wide-temperature-range operation of 1.3-/spl mu/m beam expander-integrated laser diodes grown by in-plane thickness control MOVPE using a silicon shadow mask

A new fabrication method of high-quality thickness-tapered semiconductor waveguides is proposed based on controlling in-plane thickness during MOVPE by using a comb-shaped silicon shadow mask. It was used to fabricate a 1.3-/spl mu/m-wavelength narrow-beam (less than 13/spl deg/) InGaAsP-InP laser diode, which achieved high-power (over 20 mW) operation up to 85.     

A p-silicon nanowire/n-ZnO thin film heterojunction diode prepared by thermal evaporation

This paper represents the electrical and optical characteristics of a SiNW/ZnO heterojunction diode and subsequent studies on the photodetection properties of the diode in the ultraviolet （UV） wavelength region. In this work, silicon nanowire arrays were prepared on p-type （100）-oriented Si substrate by an electroless metal deposition and etching method with the help of ultrasonication. After that, catalyst-free deposition of zinc oxide （ZnO） nanowires on a silicon nanowire （SiNW） array substrate was done by utilizing a simple and cost-effective thermal evaporation technique without using a buffer layer. The SEM and XRD techniques are used to show the quality of the as-grown ZnO nanowire film. The junction properties of the diode are evaluated by measuring current-voltage and capacitance-voltage characteristics. The diode has a well-defined rectifying behavior with a rectification ratio of 190 at -t-2 V, turn-on voltage of 0.5 V, and barrier height is 0.727 eV at room temperature under dark conditions. The photodetection parameters of the diode are investigated in the bias voltage range of ± 2 V. The diode shows responsivity of 0.8 A/W at a bias voltage of 2 V under UV illumination （wavelength = 365 nm）. The characteristics of the device indicate that it can be used for UV detection applications in nano-optoelectronic and photonic devices.     

激光辐照TiO2/SiO2薄膜损伤时间简捷测量

为了测量激光辐照薄膜的起始时间,采用了一种简洁易行的测量方法,利用波长1.06μm和1.315μm连续激光以及1.06μm单脉冲激光辐照典型薄膜光学元件,通过探测器接收激光脉冲信号和薄膜表面的激光反射信号,薄膜表面反射信号在激光辐照过程中的某个时刻发生突变,发生突变的时间对应着薄膜发生损伤的时间。得到1.06μm连续激光强度为7133W/cm2时,反射信号在0.8 s发生突变,强度为11776W/cm2时,反射信号在0.4 s发生变化;1.06μm单脉冲激光能量为48.725mJ,97.45m J,194.9m J时,薄膜损伤时间为3.63ns,2.727ns和1.09ns;1.315μm连续激光强度为2743W/cm2时,反射光信号在辐照时间t=3.44 s发生突变;强度为4128W/cm2时,薄膜表面反射光信号在辐照时间t=1.44s发生突变。结果表明,通过测量薄膜表面反射信号的突变来确定薄膜损伤的起始时间,对于薄膜抗激光加固,以及提高光电系统的抗激光能力有着重要的意义。     

Continuously tunable 1.55-/spl mu/m VCSEL implemented by precisely curved dielectric top DBR involving tailored stress

We present an optically pumped and continuously tunable 1.55-/spl mu/m vertical-cavity surface-emitting laser (VCSEL). The device shows 26-nm spectral tuning range, 400-/spl mu/W maximum output power, and 57-dBm side-mode suppression ratio. The VCSEL is implemented using a two-chip concept. The movable top mirror membrane is precisely designed to obtain a tailored air-gap length (L'=16 /spl mu/m) and a radius of curvature (ROC=4.5mm) in order to efficiently support the fundamental optical mode of the plane-concave resonator. It consists of a distributed Bragg reflector (DBR) with periodic, differently stressed silicon nitride and silicon dioxide multilayers implemented by plasma-enhanced chemical vapor deposition. The lower InP-based part, comprising the InP-InGaAsP bottom DBR and the active region, is grown monolithically using metal-organic vapor phase epitaxy.     

Fabrication of Au/PEDOT stacked electrodes for organic thin film transistors by imprinting technology

In this work, the Au/PEDOT stacked source/drain electrodes of OTFTs were fabricated by combining the micro-contact inking and reversal imprinting. The PEDOT was inked on the mold by the micro-contact process and the Au/PEDOT stacked layer was transferred on pentacene by imprinting technology. The threshold voltage, and on-off ratio, carrier mobility, and source/drain contact resistance of organic TFTs were all improved by the proposed process.     

Multiplexing of millimeter-wave signals for fiber-radio links by direct modulation of a two-mode locked Fabry-Pe/spl acute/rot laser

In this paper, we introduce generation of multiplexed signals on the millimeter-wave bands for fiber-radio systems where an optical millimeter-wave generator is based on a two-mode locked Fabry-Pe/spl acute/rot (FP) slave laser, whose injection current is directly modulated by a signal source. We qualitatively consider the distortion of the millimeter-wave signals from the FP slave laser. The distortion components on the millimeter-wave bands are induced from the simultaneous modulation of the locked modes and the nonlinear modulation response of the FP laser. Two-tone modulation of the locked FP laser is examined to evaluate the dynamic range of the millimeter-wave signals against the second- and third-order distortion components. We also perform fiber transmission of three 156-Mb/s-BPSK signals on the 60-GHz band to demonstrate fiber-radio down-link systems. The total capacity of the down-link system is discussed. In addition, two methods for multicarrier generation on the millimeter-wave bands are proposed. Multicarrier generators supported by these methods can be used as local signals for up-link millimeter-wave signals. The first method is based on multitone modulation of the FP slave laser. We attempt the down-conversion of a 52-Mb/s ASK signal on the 60-GHz band by using the millimeter-wave local signals. The second method depends on the distorted modulation of the FP slave laser by using a single continuous wave signal where the DC-bias level of the FP laser's injection current is partly under the threshold value. We confirm that five carriers on the 60-GHz band are effectively generated by using the second method. Furthermore, the influences of the chromatic dispersion effects on the millimeter-wave local signals are investigated for both methods.     

纳米VO2薄膜相变特性的红外透射表征研究

采用双离子束溅射VOx薄膜附加热处理的方式制备纳米VO2薄膜,利用X射线衍射仪和扫描电子显微镜分别对其结晶结构和表面形貌进行了测试,利用傅立叶变换红外光谱仪(FTIR)对热驱动下纳米VO2薄膜相变过程中的光学性能进行测试与分析。实验结果表明,经400℃N2热处理后,获得了由纳米颗粒组成的VO2薄膜;在所测试的红外波段,纳米VO2薄膜内颗粒发生相变的初始温度随波长的增加而升高,薄膜的相变温度点随波长增加也逐渐升高。     

Mobility enhancement by using silk fibroin in F16CuPc organic thin film transistors

High performance n-type F₁₆CuPc organic thin-film transistors (OTFTs) were fabricated on polyethylene terephthalate (PET) using silk fibroin as the gate dielectric. The average field-effect mobility (μ_FE) value in the saturation regime is 0.39 cm² V⁻¹ s⁻¹ approximately one order of magnitude higher than the reported values in the literature. A typical F₁₆CuPc OTFT exhibits an on/off current ratio of 9.3 × 10², a low threshold voltage of 0.65 V, and a subthreshold swing value of 730 mV/decade. The enhancement of μ_FE results from very good crystal quality of F₁₆CuPc on silk fibroin, supported by grazing incidence X-ray diffraction (GIXD) data.     

PI/Cr钝化对提高AlGaN/GaN HEMTs 击穿电压的研究

A novel AlGaN/GaN high electric mobility transistor（HEMT） with polyimide（PI）/chromium（Cr） as thepassivationlayerisproposedforenhancingbreakdownvoltageanditsDCperformanceisalsoinvestigated.The Cr nanoparticles firstly introduced in PI thin films by the co-evaporation can be used to increase the permittivity of PI film. The high-permittivity PI/Cr passivation acting as field plate can suppress the fringing electric field peak at the drain-side edge of the gate electrode. This mechanism is demonstrated in accord with measured results. The experimental results show that in comparison with the AlGaN/GaN HEMTs without passivation, the breakdown voltage of HEMTs with the PI/Cr composite thin films can be significantly improved, from 122 to 248 V.