ICPCVD-SiN_x对GaN/AlGaN基紫外探测器的钝化效果的研究

采用ICPCVD-SiNx薄膜对GaN/A1GaN基紫外探测器进行钝化,从薄膜绝缘特性、钝化效果两方面,对ICPCVD-SiNx、磁控溅射-SiOx、PECVD-SiOx和PECVD-SiNx四种钝化膜进行对比.制作了钝化膜/GaN MIS器件,通过测试MIS器件漏电流密度和薄膜击穿电场的大小表征薄膜绝缘性能,结果表明ICPCVD-SiNx对应的MIS器件的漏电特性最好,外加偏压为100 V时,其漏电流密度保持在1×10-7 A/cm2以下,薄膜击穿电场大于3.3 MV/cm.采用不同钝化方法制作了p-i-n型AlGaN基紫外探测器,通过计算钝化前后器件暗电流的变化,表征不同钝化方法的钝化效果.结果表明ICPCVD-SiNx钝化的器件,其暗电流比其他钝化方法的器件小近两个数量级,在-5V偏压下暗电流密度为7.52 A/cm2.     

双面Schottky势垒型GaAs粒子探测器特性

双面肖特基势垒型 Ga As粒子探测器由半绝缘砷化镓材料制成 ,器件结构为金属 -半导体-金属结构 ,该探测器能经受能量为 1 .5Me V、剂量高达 1 0 0 0 k Gy的电子、50 0 k Gy的 γ射线、β粒子、X射线等粒子的辐照测试 ,辐照后器件击穿曲线坚挺 ,反向漏电流最低为 0 .48μA.器件的另一特征是其反向漏电流与 X射线的照射量呈线性关系 .该探测器在 2 4 1Am( Eα=5.48Me V) α粒子辐照下 ,其最大的电荷收集率和能量分辩率分别为 45%和 7% .在由 90 Sr( Eβ=2 .2 7Me V)发出的 β粒子辐照下 ,探测器有最小的电离粒子谱 .该探测器对光照也有明显的响应     

双面Schottky势垒型GaAs粒子探测器特性

双面肖特基势垒型GaAs粒子探测器由半绝缘砷化镓材料制成,器件结构为金属-半导体-金属结构,该探测器能经受能量为1.5MeV、剂量高达1000kGy的电子、500kGy的γ射线、β粒子、X射线等粒子的辐照测试,辐照后器件击穿曲线坚挺,反向漏电流最低为0.48μA.器件的另一特征是其反向漏电流与X射线的照射量呈线性关系.该探测器在241Am(Ea＝5.48MeV)a粒子辐照下,其最大的电荷收集率和能量分辩率分别为45%和7%.在由90Sr(Eβ=2.27MeV)发出的β粒子辐照下,探测器有最小的电离粒子谱.该探测器对光照也有明显的响应.     

碲镉汞长波探测器暗电流仿真分析

针对n-on-p型长波Hg1-x Cdx Te红外探测器的暗电流进行建模分析,分析了不同机制对暗电流的影响,仿真分析结果和实际结果能够较好地匹配。得出探测器的工作状态暗电流Idark=9×10-10 A,工作电阻Rr=109Ω,品质因子R0A=20Ωcm2。从仿真分析结果得出,在现有工艺下,Shockley-Read-Hall(SRH)复合和表面漏电是影响暗电流的最主要的非本征因素,其中SRH复合速率为2×1016/s·cm3,当表面态到达1×1012 cm-2,器件会出现严重的表面沟道。     

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。     

基于CVD单层MoS_2 FET的光电探测器北大核心

通过化学气相沉积(CVD)工艺在SiO_2/Si衬底生长出MoS_2材料,对材料进行喇曼光谱表征,验证了单层MoS_2的存在;基于CVD生长的单层MoS_2完成了晶圆级背栅场效应晶体管(FET)光电探测器的工艺研发;对MoS_2 FET器件进行了电学特性表征,开关比可达到105数量级,场效应迁移率约为1 cm2·V-1·s-1,栅极漏电流为10-10 A数量级;对MoS2FET器件的光电特性进行了表征,该光电探测器具有普通光电导探测器的基本光电特性,其光电流随光照强度的增强以及源漏电压的增加而增加,同时由于栅极的调制提高了光电探测器的灵活性。通过控制栅极电压能够控制MoS2FET光电探测器的暗电流大小,实现对探测器η参数的有效调制。最后通过器件能带图对MoS_2 FET光电探测器的光电特性进行了阐释,为其走向实际应用奠定了理论基础。     

6H-SiC高反压台面pn结二极管

在可商业获得的单晶6H-SiC晶片上,通过化学气相淀积,进行同质外延生长;并在此6H-SiC结构材料上,利用反应离子刻蚀和接触合金化技术,制作台面pn结二极管．详细测量并分析了器件的电学特性,测量结果表明此6H-SiC二极管在室温、空气介质中,-10V时,漏电流密度为2.4×10-8A/cm2,在反向电压低于600V及接近300℃高温下都具有良好的整流特性．     

基于CMOS工艺的双层非制冷热敏电阻型红外探测器

采用0.5μm标准CMOS工艺和微机械加工工艺,设计并制作了低成本双层非制冷热敏电阻型红外探测器。探测器采用隐藏桥腿式微桥结构,使用表面牺牲层技术实现,其中包括Al、W和Si3种牺牲层材料。CMOS工艺加工完成后,双层微桥结构的微机械加工过程只需进行湿法腐蚀即可,成本较低。对双层红外探测器的热性能和光电特性进行测试,其热导为1.96×10-5 W/K,热容为2.23×10-8 J/K,热时间常数为1.14ms。当红外辐射调制频率为10Hz时,双层红外探测器的电压响应率为2.54×104 V/W,探测率为1.6×108 cm·Hz1/2/W。     

4H-SiC混合PN/Schottky二极管的研制

报道了4H-SiC混合PN/Schottky二极管的设计、制备和特性．该器件用镍作为肖特基接触金属,使用了结终端扩展（JTE）技术．在肖特基接触下的n型漂移区采用多能量注入的方法形成P区而组成面对面的PN结,这些PN结将肖特基接触屏蔽在高场之外,离子注入的退化是在1500℃下进行了30min．器件可耐压600V,在600V时的最小反向漏电流为1×10-3A/cm2．1000μm的大器件在正向电压为3V时电流密度为200A/cm2,而300μm的小尺寸器件在正向电压为3.5V电流密度可达1000A/cm2．     

气态源分子束外延8元In0.53Ga0.47As/InP光伏探测器阵列

采用气态源分子束外延(GSMBE)生长技术结合常规半导体工艺制成了正进光台面型8元In0.53Ga0.47As/InP光伏探测器阵列,并对其特性进行了测量,结果表明GSMBE生长的材料具有很好的均匀性.探测器阵列在室温下具有良好的性能,在-10 mV反偏下探测器的暗电流约173 pA,单元间的相对标准差为1.3%;器件的峰值探测率为4.7×1011 cm·Hz1/2/W,单元间的相对标准差为0.9%.     

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.     

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.     

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.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks