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.     

AlGaN MSM紫外探测器

用通过MOCVD生长的未掺杂的n-Al0．3Ga0．7N制备了金属-半导体-金属 (MSM)结构紫外探测器。器件在2．5V偏压时的暗电流为1pA,在6．5V偏压时的暗电流为1nA．在1V偏压下和298nm波长处,探测器的电流响应率为0.038A／W,在300nm 波长处有陡峭的截止边,这与文献中介绍的AlxGa1-xN探测器在x=0．3时截止波长为 300nm相一致。     

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.     

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.     

Al0.3Ga0.7N MSM紫外探测器研究

用MOCVD生长的未掺杂的疗n-Al0．3Ga0．7N制备了MSM结构紫外探测器。器件在5.3V偏压时暗电流为1nA，在315nm波长处有陡峭的截止边，在1V偏压下305nm峰值波长处探测器的电流响应率为0．023A／W，要进一步提高器件的响应率，方法之一是优化器件的结构参数，尽量减小叉指电极的宽度。为了检验Au／n-Al0．3Ga0．7N肖特基接触特性，电击穿MSM右边结，由正向I-V特性曲线计算出理想因子n～1．05，零偏势垒高度ФB0～1．16eV，表明形成的Au／n-Al0．3Ga0．7N肖特基结较为理想。     

基于银纳米薄膜欧姆接触的高波长选择性紫外探测器研究

常规的半导体紫外探测器波长响应范围宽,而紫外光的应用具有较强的波长选择性,如320nm波段的紫外光在医学方面有重要的应用,因此,具有高波长选择性的紫外探测器的研制有重要意义。文章采用GaN基p-i-n探测器结构,通过在p区覆盖银纳米薄膜作为欧姆接触层和波长选择透射层,成功制备了对320nm波段紫外光高选择性探测的紫外探测器,器件性能如下:70nm银层的紫外光透射率峰值超过30%,器件在-5V偏压下的暗电流为10-12 A量级,响应峰值为0.06A/W,响应峰发生在325nm处,光谱响应峰半高宽约30nm。     

p-i-n结构GaN光电探测器性能的研究

近年来,可见盲与太阳盲光电探测器在火灾监控、太空通信和导弹尾焰探测等方面的应用引起了越来越多的关注。由于氮化镓(GaN)是直接宽带隙半导体材料,所以成为了在可见区与紫外区的光电器件的首选材料,而p-i-n结构的器件因其响应度高、暗电流低、便于集成等优点倍受人们的青睐。采用金属有机气相外延(MOCVD)法制备了p-i-n结构的GaN紫外光电探测器。在此基础上,采用N2气氛下热退火处理的方法,提高了p型GaN层的载流子浓度,从而降低了器件的暗电流。器件在1 V偏压下,暗电流仅为65 pA。器件在1 V偏压下的最大响应度值出现在361 nm处,大小为0.92 A/W。     

AlxGa1-xN日盲紫外探测器及其焦平面阵列

报道了320×256元AlxGa1-xN日盲型紫外探测器及其焦平面阵列探测器的研制情况,介绍了材料生长、器件制备工艺和器件的光电特性.器件的开启电压大于3.5 V,-0.5 V偏压时暗电流小于1.2×10-12A(φ=300 μm台面),光谱响应范围260～280 nm,268 nm峰值波长的响应度大于0.095 A/W.器件实现了日盲紫外成像演示.     

β-Ga_2O_3薄膜的分子束外延生长及其紫外光敏特性研究

采用分子束外延(MBE)方法在Al2O3(0001)基片上生长了β-Ga2O3薄膜,利用XRD、SEM和AFM对薄膜的结构和形貌特性进行了表征。制作了基于β-Ga2O3薄膜的金属-半导体-金属(MSM)结构紫外探测器并对其进行了电学特性测试,结果表明:在20 V偏压下,器件的暗电流为8 nA;在波长为254 nm、光照强度为13×10–6W/cm2的紫外光照射下,器件的光电流为624 nA;器件的光电流与暗电流比值为78,光响应度达360 A/W,表现出明显的日盲紫外光响应特性。     

金属-半导体-金属(MSM)结构4H-SiC紫外光电探测器的研制

MSM结构探测器具有结构与工艺简单、制备成本低、量子效率高等特点而在探测器应用中得到重视。本文制备了采用镍作为肖特基接触形成的MSM4H—SiC紫外光电探测器，并测量和分析了在不同的偏压下其光电特性。结果表明，该探测器的暗电流非常小，在偏压为15V的时候，漏电流密度约为70nA／cm^2，光电流比暗电流高约2个数量级，其光谱响应表明，其最高光谱响应与380nm的比值约为1000倍，说明该探测器具有良好的紫外可见比。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

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.     

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.     

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.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.