薄p型层GaN基p-i-n型紫外探测器的反向漏电特性

制备了薄p型层GaN基p-i-n型紫外探测器,并对其反向漏电特性进行了研究。探测器材料采用金属有机化学气相沉积(MOCVD)方法在蓝宝石衬底上外延生长获得,p-GaN的厚度为30nm。基于该材料制作了具有共面电极的探测器器件,并采用SiO2对刻蚀侧壁进行了钝化。测试结果表明,结面积为1.825×10-4cm2的器件在-1V时的反向漏电流面密度为3.0×10-9 A/cm2,优质因子达到3.7×109Ω.cm2。     

利用ICPCVD方法在GaN上沉积氧化硅薄膜的特性

使用感应耦合等离子体化学气相沉积(Inductively coupled plasma chemical vapor deposition,ICPCVD)方法在GaN上沉积SiOx薄膜,生长参数中采用不同RF功率,研究RF功率对薄膜物理性能和电学性能的影响.结果发现,随着RF功率增大,薄膜应力增大,表面粗糙度减小,薄膜致密度增大.选择最优的RF功率参数,制作了SiOx/nGaN金属-绝缘体-半导体(metal-insulator-semiconductor,MIS)器件,结果得到薄膜漏电流密度在外加偏压为90V时小于1×10-7A/cm2,SiOx/n-GaN界面态密度为2.4×1010eV-1cm-2.表明利用ICPCVD低温沉积的SiOx-GaN界面态密度低,薄膜绝缘性能良好.     

GaN基肖特基结构紫外探测器

在蓝宝石(0001)衬底上采用低压金属有机物化学气相沉积(MOCVD)方法生长GaN外延层结构,以此为材料制作了GaN基肖特基结构紫外探测器.测量了该紫外探测器的暗电流曲线、C-V特性曲线、光响应曲线和响应时间曲线.该紫外探测器在5V偏压时暗电流为0.42nA,在10V偏压时暗电流为38.5nA.在零偏压下,该紫外探测器在250nm～365nm的波长范围内有较高的响应度,峰值响应度在363nm波长处达到0.12A/W,在365nm波长左右有陡峭的截止边;当波长超过紫外探测器的截止波长(365nm左右),探测器的响应度减小了三个数量级以上.该紫外探测器的响应时间小于2μs.     

介质膜性质及表面处理对GaN HEMT特性的影响

GaN HEMT器件经过钝化后,抑制电流崩塌效应明显,但同时产生其他负面效应,为了改善目前GaN HEMT钝化后漏电增加和击穿电压减小等情况,研究了钝化技术对GaN HEMT电流特性的影响,包括介质膜应力、折射率和表面预处理与器件饱和电流、电流崩塌量的关系,优化了表面预处理和钝化工艺条件.实验效果在CaN HEMT电特性上的改善明显.结果表明,采用折射率为2.1～2.2的SiN钝化膜,饱和电流密度增加到1 100 mA/mm,电流崩塌量小于10%,肖特基接触反向偏压为-20 V时泄漏电流达10-5A数量级.     

GaN基p-i-n型紫外探测器钝化工艺研究

钝化层膜系的选择及其工艺的优化对降低GaN基紫外探测器的漏电流和提升其可靠性是至关重要的。文章采用多种钝化层：等离子体增强化学气相沉积生长的Si₃N₄(PECVD-Si₃N₄)、电感耦合等离子体化学气相沉积生长的Si₃N₄(ICPCVD-Si₃N₄)和SiO₂(ICPCVD-SiO₂)以及等离子原子层沉积生长的Al₂O₃(PEALD-Al₂O₃),分别制备了GaN基金属-绝缘体-半导体(MIS)器件，并对MIS器件的电流-电压(I-V)和电容-电压(C-V)特性进行了对比研究。采用PECVD-Si₃N₄作为钝化层的GaN基MIS器件具有较低的漏电流；在双层PECVD-Si₃N₄钝化层中插入PEAL...     

GaN基肖特基结构紫外探测器

在蓝宝石 (0 0 0 1)衬底上采用低压金属有机物化学气相沉积 (MOCVD)方法生长GaN外延层结构 ,以此为材料制作了GaN基肖特基结构紫外探测器 .测量了该紫外探测器的暗电流曲线、C V特性曲线、光响应曲线和响应时间曲线 .该紫外探测器在 5V偏压时暗电流为 0 4 2nA ,在 10V偏压时暗电流为 38 5nA .在零偏压下 ,该紫外探测器在2 5 0nm～ 36 5nm的波长范围内有较高的响应度 ,峰值响应度在 36 3nm波长处达到 0 12A/W ,在 36 5nm波长左右有陡峭的截止边 ;当波长超过紫外探测器的截止波长 (36 5nm左右 ) ,探测器的响应度减小了三个数量级以上 .该紫外探测器的响     

AlInGaN/GaN PIN紫外光电探测器的研制

用AlInGaN四元合金代替AlGaN作为PIN探测器的有源层,研制出AlInGaNPIN紫外探测器.详细介绍了该器件的结构设计和制作工艺,并对器件进行了光电性能测试.测试结果表明,器件的正向开启电压约为1.5 V,反向击穿电压大于40 V;室温-5 V偏压下,暗电流为33 pA,350 nm处峰值响应度为0.163 A/W,量子效率为58%.     

一维阵列MSM 4H-SiC紫外光电探测器的研制

采用Ni/Au作为肖特基接触制备了一维阵列MSM 4H-SiC紫外光电探测器,并测量和分析了阵列器件的Ⅰ-Ⅴ、光谱响应特性.结果表明,阵列探测器性能均匀性好,击穿电压均高于100V.阵列中单器件暗电流小,在偏压为20V的时候,最大暗电流均小于5pA(电流密度为5nA/cm2),光电流比暗电流高3个数量级以上.其光谱响应表明,单器件在电压为20V时的响应度约为0.09A/W,比400nm时的比值均大5000倍,说明探测器具有良好的紫外可见比.     

基于斜台面工艺的背照式GaN雪崩探测器制备

对基于斜台面工艺的背照式pin型GaN紫外雪崩探测器制备进行了简要介绍.通过斜台面制作工艺的对比优化研究,完成了GaN紫外雪崩探测器的低损伤斜台面制作,器件测试结果表明,高质量斜台面能够有效抑制雪崩探测器的表面提前击穿,器件暗电流特性优良,获得了超高雪崩增益的GaN紫外雪崩探测器.     

平面型InGaAs红外探测器I-V特性研究

采用闭管扩散方式,利用SiO2及Si3N4扩散掩膜在NIN型InP/In0.53Ga0.47As/InP外延材料上制备了两种不同的平面型InGaAs红外探测器,研究了室温下不同扩散区面积的两种器件的正向I-V特性及反向暗电流密度与器件周长面积比的关系,结果表明,扩散区边缘的钝化是平面型InGaAs探测器的制备过程中非常重要的一环,而且Si3N4薄膜的钝化效果优于SiO2薄膜。室温下和-0.1V偏压下,采用Si3N4扩散掩膜的器件的暗电流密度约为20nA/cm2。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.