Ferroelectric materials for dynamic-memory integrated circuits

The possibilities of using ferroelectric materials for new generations of integrated circuits for high-density dynamic memory (up to 1 Gbit per crystal) are discussed. The correspondence of the specific capacitance and leakage currents of thin film ferroelectric capacitors to the requirements for integrated circuits with various information capacities is examined. It is shown that the capacitance-voltage characteristic of the ferroelectric strongly influences the specific capacitance and the rate of decrease of the voltage across the capacitors when they are discharged in the process of storing information. The prospects for increasing the specific capacitance of memory capacitors using relaxor ferroelectrics are examined. Zh. Tekh. Fiz. 69, 89–92 (May 1999)     

A versatile modular computational tool for complex optoelectronic integrated circuits simulation

A novel graphical computational tool to simulate a wide variety of complex optoelectronic integrated circuits is presented. Based upon a modular approach, this tool reduces the optical circuit into a sequence of interconnected building blocks, each one performing a specific data-flow oriented function onto an input optical stream. The modularity and the flow-based interconnectivity makes this simulator flexible and powerful, yet intuitive. Its execution speed is evaluated using a sophisticated amplifier simulation module that is compared against its replica written in a text-based programming language. More than four times outperformance is reported. The simulator capabilities are further demonstrated through an application example in the field of optical data processing: the analysis of a semiconductor optical amplifier-based Mach–Zehnder interferometer operated as wavelength converter for signals modulated at 40 Gb/s. This simulator represents an attractive alternative to more traditional approaches.     

Organic materials for integrated optics

Organic materials have been shown to be quite useful for the fabrication of integrated-optics devices. The fabrication of low loss (0.1 dB cm^?1) sheet-film waveguides and studies of high gain (100 dB cm^?1) thin-film laser amplifiers and oscillators are reviewed. Techniques employing photosensitive components have made it possible to make three-dimensional waveguides which have the lowest losses reported so far (0.2 dB cm^?1 in single-mode structures). Surface and index gratings and related devices made with organic materials are also discussed.     

Analysis of optical crosstalk within optoelectronic integrated circuits including lasers and photodetectors

Optical crosstalk from a 1.3 μm laser to a 1.55 μm photodiode on a single InP substrate, and its suppression within 1.3 μm/1.5 μm Y-junction transceiver OEICs, has been analyzed experimentally. The results indicate that the optical crosstalk suppression is limited by the accumulated light in the OEIC substrate coming mainly from the spontaneous emission of the integrated laser and from stray light at the laser–waveguide butt joint interface. For OEICs, integrating lasers and photodetectors, the achievable optical intra-chip crosstalk at present will be in the range of 30–40 dB at the required small die dimensions. Received: 16 May 2001 / / Published online: 23 October 2001     

Organic-inorganic materials for fabrication of integrated optical circuits

In the last few years, ORganically MOdified SIlicates (ORMOSILS) [R_xSi(OR)_4−x] prepared by sol-gel process were particularly attractive for integrated optics fabrication. A composition based on 3-(trimethoxysilyl)propylmethacrylate (MAPTMS) has already allowed the industrial fabrication of optical integrated devices. For this kind of materials, the polymerization of the organic network is typical of free radical curing.In this work, we try to obtain waveguides with another hybrid precursor [2-(3,4-epoxycyclohexylethyltrimethoxysilane)] using cationic polymerization. The main advantage of cationic polymerization is its ability to allow spontaneous cure reaction in presence of oxygen, in contrast with radical polymerization. We choose cycloaliphatic compounds because of their well-known high polymerization rates. The polymerization of the organic network of this hybrid material requires a cationic photoinitiator.The purpose of this paper is dedicated to the inorganic part of the material. Hydrolysis and polycondensation are followed by ²⁹Si NMR. The main objective is to obtain the highest reactive multifunctional oligomer with the lowest OH groups content.Based on our results, we obtained 3D waveguides with a cross-section of 5 μm × 5 μm.     

Electromigration in integrated circuits

We review the mechanism of integrated circuit failure known as “electromigration.” Electromigration is a physical wearout process that operates primarily in the on-chip interconnections of an integrated circuit. It is caused by the currents that run through those interconnections. The first part of the review introduces the founding principles of electromigration and the research history upon which those principles are based. The second part introduces and reviews the increasingly relevant issue of pulsed current electromigration, and the final part contains a relatively detailed review of a recent study of pulsed current electromigration.     

Graphene applications in electronic and optoelectronic devices and circuits

Recent progress of research for graphene applications in electronic and optoelectronic devices is reviewed, and recent developments in circuits based on graphene devices are summarized. The bandgap-mobility tradeoff inevitably constrains the application of graphene for the conventional field-effect transistor （FET） devices in digital applications. However, this shortcoming has not dampened the enthusiasm of the research community toward graphene electronics. Aside from high mobility, graphene offers numerous other amazing electrical, optical, thermal, and mechanical properties that continually motivate innovations.     

Polymer-based photonic integrated circuits

A myriad of passive and active guided-wave devices has been successfully demonstrated using the photolime gel polymer. These include high density linear and curved channel waveguide arrays, electro-optic modulator and modulator arrays, highly multiplexed waveguide holograms for wavelength division demultiplexing and optical interconnects, waveguide lens, and rare-earth ion-doped polymer waveguide amplifiers. A single-mode linear channel waveguide array with device packaging density of 1250 channels cm^-1 has been achieved. The first 12-channel wavelength division demultiplexer working at 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930 and 940 nm on a GaAs substrate is also described in this paper. A polymer-based electro-optic travelling wave modulator with 40 GHz electrical bandwidth is further delineated. A rare-earth ion-doped polymer waveguide amplifier working at 1.06 μm with 8.5 dB optical gain is also achieved using this polymer matrix. The tunability of the waveguide refractive index of photolime gel polymer allows the formation of a graded index (GRIN) layer. As a result, these active and passive guided wave devices can be realized on any substrate of interest. High quality waveguides (loss<0.1 dB cm^-1) have been made on glass, LiNbO3, fused silica, quartz, PC board, GaAs, Si, Al, Cu, Cr, Au, Kovar, BeO, Al₂O₃ and AIN.     

Modeling and analysis of silicon-on-insulator elliptical microring resonators for future high-density integrated photonic circuits

We propose a novel resonator containing an elliptical microring based on a silicon-on-insulator platform. Simulations using the three-dimensional finite-difference time-domain method show that the novel elliptical microring can efficiently enhance the mode coupling between straight bus waveguides and resonator waveguides or between adjacent resonators while preserving relatively high intrinsic quality factors with large free spectral range. The proposed resonator would be an alternative choice for future high-density integrated photonic circuits.     

硅基光电集成器件研究进展

随着器件结构与制作工艺的不断创新与完善，硅基发光器件已经可以实现室温下的有效工作，外量子效率可达到0．1％；低功耗的硅基高速调制器件的调制速率达到1GHz以上；而硅基光探测器对1300nm与1550nm波长的探测响应度也已分别达到了0．16mA／W和0．08mA／W．文章对硅基光电器件的研究进展情况进行了概述，并着重对几种器件的结构及工作原理进行了分析．     

硅基集成电路的发展和新一代栅极氧化物材料的研究现状

随着科学技术的进步和集成电路市场日益扩大的需求，硅基集成电路的集成度越来越高，而集成度的提高是以其核心器件金属氧化物半导体场效应晶体管(MOSFET)的特征尺寸逐渐减小为基础的。当栅极Si02介电层的厚度减小到原子尺度大小时，由于量子效应的影响，Si02将失去介电特性，因此必须寻找一种新的高介电常数(high—K)的氧化物材料来代替它。如今世界上许多国家都开展了替代Si02的介电氧化物材料的研究工作。文章介绍了栅极介电层厚度减小带来的影响，栅极Si02介电层的高尺氧化物材料的要求和租选，并对近期高介电常数氧化物材料的研究状况作了简要的介绍和评述。     

Amorphous silicon logic integrated circuits

Amorphous silicon thin-film integrated circuits, with between 4 and 18 transistor functions per chip, have been fabricated on glass substrates. The amorphous silicon and the dielectric layers are deposited by rf glow discharge. The circuits have been designed to realize basic logic functions such as inverters, NAND and NOR gates, and addressable memory cells. For the first time, an amorphous silicon flip flop requiring a supply voltage of only 4.5 V has been manufactured. The logic voltage levels of the flip flop are compatible with standard bipolar TTL circuits. Measurements on an inverter chain show a typical propagation delay time of 70 s and a power-delay-time product of 65 pJ. All of the circuits use n-channel enhancement type load transistors instead of integrated ohmic load resistors. The channel length of the driver transistors is 15 m with a gate source/drain overlap of 7.5 m. Experimental geometry ratios range from =2.25 to =21. Generally, the driver transistors exhibit on/off ratios greater than 10⁶ for supply voltages smaller than 5 V. At these voltages the measured on-currents per unit channel width are in the order of 5...10nA/m.The influence of the geometry ratio on static inverter characteristic and switching speed is discussed by means of a simple model. Two different manufacturing schemes for the fabrication of the integrated circuits are outlined. Mask layouts and experimental transfer characteristics of several integrated circuits are presented.     

集成电路微互连结构中的热迁移

高工作电流在集成电路微互连结构中产生大量焦耳热,引起局部区域的温升、形成高温度梯度,金属原子沿着温度梯度反向运动发生热迁移.热迁移是集成电路微互连失效的主要原因之一.阐述了热迁移原理、失效模式及原子迁移方程.综述和分析了在单纯温度场、电场和温度场耦合等不同载荷条件下金属引线和合金焊料的热迁移研究.归纳并提出了集成电路微互连结构热迁移研究亟待解决的问题. 关键词： 集成电路 微互连 热迁移     

石墨烯-硅基混合光子集成电路

近年来硅基光子学已经慢慢走向成熟,它被认为是未来取代电子集成电路,实现下一代更高性能的光子集成电路的关键技术.这得益于硅基光子器件与现代的互补金属氧化物半导体工艺相兼容,能够实现廉价的大规模集成.然而,由于受硅材料本身的光电特性所限,在硅基平台上实现高性能的有源器件仍然存在着巨大挑战.石墨烯-硅基混合光子集成电路的发展为解决这一问题提供了可行的方案.这得益于石墨烯作为一种兼具高载流子迁移率、高电光系数和宽带吸收等优点的二维光电材料,能够方便地与现有硅基器件相集成,并充分发挥自身的光电性能优势.本文结合我们课题组在该领域研究的一些最新成果,介绍了国际上在石墨烯-硅基混合光子集成电路上的一些重要研究进展,涵盖了光源、光波导、光调制器和光探测器四个重要组成部分.     

低维光电材料缺陷与界面增强拉曼散射

近年来,一系列新型低维光电材料相继涌现,展现出优异的性能.这些光电材料与表面增强拉曼散射(SERS)技术相结合,显示出巨大的应用潜力,有望成为高灵敏SERS活性基底.缺陷与界面调控是低维光电材料SERS应用的重要策略,本文将重点介绍新型低维光电材料缺陷与界面增强拉曼散射的种类和增强机理.通过对缺陷与界面增强拉曼散射的应...     

一种光电混合集成有源光双稳器件

本文报道一种光电混合集成的有源双稳态器件,它仅由一只半导体激光器,两只PIN光电探测器及几只电子元器件构成.实验上得到了光学迟滞回线,显示了光开关、光存储、光脉冲整形等功能.文中简述了器件工作原理,光电混合集成制作工艺技术及性能指标.     

Organic optoelectronic device fabrication using standard UV photolithography

The fabrication of organic optoelectronic devices requires patterning techniques that are compatible with organic semiconductor materials. Photolithography represents, by far, the dominant patterning approach for inorganic electronics and optoelectronics. High speed, parallel patterning capability, high resolution, and the availability of standard equipment make this technology also very attractive for applications in the field of organic semiconductor technology. In the present paper we present a successful implementation of photolithography to fabricate organic diodes. This process provides the basis for a future high‐resolution monolithic integration of organic optoelectronic and photonic devices into one photonic circuit. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Yield estimation of metallic layers in integrated circuits

In the existing models of estimating the yield and critical area, the defect outline is usually assumed to be circular, but the observed real defect outlines are irregular in shape. In this paper, estimation of the yield and critical area is made using the Monte Carlo technique and the relationship between the errors of yield estimated by circular defect and the rectangle degree of the defect is analysed. The rectangular model of a real defect is presented, and the yield model is provided correspondingly. The models take into account an outline similar to that of an original defect, the characteristics of two-dimensional distribution of defects, the feature of a layout routing, and the character of yield estimation. In order to make the models practicable, the critical area computations related to rectangular defect and regular (vertical or horizontal) routing are discussed. The critical areas associated with rectangular defect and non-regular routing are developed also, based on the mathematical morphology. The experimental results show that the new yield model may predict the yield caused by real defects more accurately than the circular model. It is significant that the yield is accurately estimated using the proposed model for IC metals.     

CMOS monolithic optoelectronic integrated circuit for on-chip optical interconnection

A monolithic silicon CMOS optoelectronic integrated circuit (OEIC) is designed and fabricated using standard 0.35-μm CMOS technology. This OEIC monolithically integrates light emitting diode (LED), silicon dioxide waveguide, photodetector and receiver circuit on a single silicon chip. The silicon LED operates in reverse breakdown mode and can emit light at 8.5 V. The output optical power is 31.2 nW under 9.8 V reverse bias. The measured spectrum of LED showed two peaks at 760 nm and 810 nm, respectively. The waveguide is composed of silicon dioxide/metal multiple layers. The responsivity of the n-well/p-substrate diode photodetector is 0.42 A/W and the dark current is 7.8 pA. The LED-emitted light transmits through the waveguide and can be detected by the photodetector. Experimental results show that on-chip optical interconnects are achieved by standard CMOS technology successfully.