高压BCD工艺优化对NLDMOS管的性能影响

基于SMIC 0.18 μm HVBCD工艺,移除了3层掩模板。调整器件的结构参数,对横向双扩散MOS管(NLDMOS)进行了分批流片。该NLDMOS通过了电学性能合格测试。对源漏击穿电压BVds、比导通电阻Ron进行了测试和分析。结果表明,BVds达到59.2 V,Ron为50.5 mΩ·mm²。与原有的HVBCD工艺的电参数保持一致。该NLDMOS的栅极耐压值达到40 V,同时降低了成本,缩短了生产周期。     

一种超低比导通电阻的L型栅漏极LDMOS

提出了一种具有超低比导通电阻的L型栅漏极LDMOS器件。该器件在两个氧化槽中分别制作L型多晶硅槽栅。漏极n型重掺杂区向下延伸,与衬底表面重掺杂的n型埋层相接形成L型漏极。L型栅极不仅可以降低导通电阻,还具有纵向栅场板的特性,可有效改善表面电场分布,提高击穿电压。L型漏极为电流提供了低阻通路,降低了导通电阻。另外,氧化槽折叠漂移区使得在相同耐压下元胞尺寸及导通电阻减小。二维数值模拟软件分析表明,在漂移区长度为0.9 μm时,器件耐压达到83 V,比导通电阻仅为0.13 mΩ·cm²。     

一种具有变深槽电容的横向功率p-MOSFET

提出了一种含介质深槽的横向p沟道功率MOSFET(p-MOSFET)。深槽内填充了线性组合的高介电常数(high-k)介质和二氧化硅,以调变寄生的深槽电容(CDT),使CDT充电电荷增大且使该充电电荷沿纵向接近均匀分布。在深槽一侧,通过提高p型漂移区剂量来提供负极板充电电荷,在深槽另一侧,通过增设n型区来提供正极板充电电荷。两侧漂移区的电荷补偿效应均得到增强,器件性能获得提高。仿真结果表明,当击穿电压VB为450 V时,器件的比导通电阻RON,SP为9.5 mΩ·cm²,优值达21.3 MW/cm²,优值为现有器件的2.7倍。该项研究成果为功率集成电路提供了更优的器件选择。     

一种具有鳍状阳极的垂直GaN功率二极管

针对垂直GaN肖特基二极管击穿电压低、泄漏电流大等问题,提出了一种具有鳍状(Fin)阳极结构的高压垂直GaN功率二极管。该结构利用阳极金属与GaN半导体之间的功函数差耗尽二极管阳极与阴极之间的导电沟道,实现二极管关断及反向耐压的功能,因此,阳极不再需要进行肖特基接触,仅需欧姆接触即可。通过优化Fin阳极结构参数,新结构同时实现高击穿电压和低正向导通压降,该器件的击穿电压为1 791 V(@ 1×10-4 A/cm²),正向导通压降为0.815 V(@ 100 A/cm²),导通电阻仅为0.73 mΩ·cm²且具有高的温度稳定性,开态电流摆幅高达1×10¹²量级。     

一种电荷平衡结构的沟槽MOSFET的优化设计

为了降低传统沟槽MOSFET的导通电阻和栅漏电容,科研人员提出一种具有电荷平衡结构的SG-RSO MOSFET。在此基础上,利用电荷平衡理论计算出SG-RSO MOSFET结构的主要参数,并借助TCAD仿真软件对外延层厚度及其掺杂浓度、场板氧化层厚度和沟槽深度等主要参数进行合理优化设计。最终,仿真得到击穿电压为92.6 V、特征导通电阻为19.01 mΩ·mm²、特征栅漏电容为1.45 nF·cm-2的SG-RSO MOSFET。该器件性能优于传统沟槽MOSFET。     

JTE终端结构4H-SiC JBS二极管的击穿特性研究

研究了JTE终端结构4H-SiC JBS二极管的击穿特性。首先,理论模拟了JTE终端横向长度、离子注入剂量和界面电荷对击穿电压的影响。对工艺条件进行优化,制作了JTE终端结构4H-SiC JBS二极管。测试结果表明,器件的正向电压为1.52 V,特征导通电阻为2.12 mΩ·cm²,击穿电压为1 650 V。接着,研究器件的变温电流-电压特性发现,正向电流主要为热发射机制,而反向电流与电压、温度有很强的依赖关系。最后进行了高温反偏应力老化测试,结果表明,击穿电压呈下降趋势。     

利用P型场环调节表面电场的积累层LDMOS

提出了一种在N型外延层中带有P型场环的积累层LDMOS。当器件耐压时,N型漂移区中浮空P型场环能调节漂移区的电场分布,以提高器件的耐压。当器件正向导通时,漂移区上方介质层的多晶硅二极管会在漂移区表面形成一层电子积累层,大幅提高器件的导电能力,从而降低器件的比导通电阻。数值仿真结果表明,该LDMOS的比导通电阻从传统结构的371 mΩ·cm²降低到60.9 mΩ·cm²。相比于没有场环的传统结构,该LDMOS的耐压从660 V提高到765 V。     

U型高K介质膜槽栅垂直场板LDMOS

近年来,随着汽车电子和电源驱动的发展,集成度较高的LDMOS作为热门功率器件受到了关注,如何提高其击穿电压与降低其比导通电阻成为提高器件性能的关键。基于SOI LDMOS技术,文章提出了在被4 μm的高K介质膜包围的SiO₂沟槽中引入垂直场板的新型结构。与传统沟槽LDMOS相比,垂直场板和高K介质膜充分地将电势线引导至沟槽中,提高了击穿电压。此外垂直场板与高K介质和漂移区形成的MIS金属-绝缘层-半导体电容结构能增加漂移区表面的电荷量,降低比导通电阻。通过二维仿真软件,在7.5 μm深的沟槽中引入宽0.3 μm、深6.8 μm的垂直场板,实现了具有300 V的击穿电压和4.26 mΩ·cm²的比导通电阻,以及21.14 MW·cm-2的Baliga品质因数的LDMOS器件。     

一种带埋层的超低比导通电阻槽型LDMOS

提出了一种带n型浮空埋层的超低比导通电阻的变k槽型LDMOS(TLDMOS)。新结构在漂移区内引入变介电常数(VK)的深槽结构和自驱动的U型p区,不仅可提高漂移区的掺杂浓度,还可优化体内电场分布。衬底中引入的n埋层在器件阻断时进一步调制漂移区的电场分布。同时,额外p衬底/n埋层结的引入提高了LDMOS的纵向耐压。导通时,由于集成低压电源施加于U型p区,在其周围产生的电子积累层使器件在不增加栅电荷的情况下显著降低了比导通电阻(Ron,sp)。仿真结果表明,与传统TLDMOS相比,在相同元胞尺寸下,新结构的击穿电压提高了59.3%,Ron,sp降低了86.3%。     

带有P型埋层的新型双栅SOI MOSFET

本文提出一种超低比导通电阻(Ron,sp)可集成的SOI 双栅triple RESURF (reduced surface field)的n型MOSFET (DG T-RESURF)。这种MOSFET具有两个特点：平面栅和拓展槽栅构成的集成双栅结构(DG),以及位于n型漂移区中的P型埋层。首先, DG形成双导电通道并且缩短正向导电路径,降低了比导通电阻。DG结构在反向耐压时起到了纵向场板作用,提高了器件的击穿电压特性。其次, P型埋层形成triple RESURF结构 (T-RESURF),这不仅增加了漂移区的浓度,而且调节了器件的电场。这在降低了比导通电阻的同时提高了击穿电压。最后,与p-body区连接在一起的P埋层和拓展槽栅结构,可以显著降低击穿电压对P型埋层位置的敏感性。通过仿真,DG T-RESURF的击穿电压为325V,比导通电阻为8.6 mΩ?cm2,与平面栅single RESURF MOSFET(PG S-RESURF)相比,DG T-RESURF的比导通电阻下降了63.4%,击穿电压上升9.8%。     

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.