A Monolithically Integrated 12V/5V Switch-Capacitor DC-DC Converter

A monolithically integrated 12V/SV switch capacitor DC-DC converter with structure-simplified main circuit and control circuit is presented. Its topological circuit and basic operating principle are discussed in detail. It is shown that elevated operating frequency, increased capacitance and reduced turn-on voltage of the diodes can make the converter's output characteristics improved. Reducing resistance of the equivalent resistors and other parasitic parameters can make the operation frequency higher. As a feasible efficient method to fabricate monolithically integrated converter with high frequency and high output power, several basic circuits are parallelly combined where the serial-parallel capacitance is optimized for the maximum output power. The device selection and its fabrication method are presented. A feasible integration process and its corresponding layout are designed. All active devices including switching transistors and diodes are integrated together with all passive cells including capacitors and resistor on a single chip based on BiMOS process,as has been verified to be correct and practical by simulation and chip test.     

A Monolithically Integrated 12V/5V Switch-Capacitor DC-DC Converter

Motivated by the battery-operated applications that demand compact,lightweight andefficient DC-DC converters,many kinds of converter circuits have been published.Amongthem,resonantconverters and the soft-switching convertershave greatl...     

Test device structures for integrated circuit design,process technology development and evaluation

In the present paper, mask contours of npn transistors, pnp lateral transistors, diffused and pinch resistors, bridge and Greek cross sheet resistors, metal to doped silicon region contact resistors, parasitic pnp transistors, test diodes and alignment marks have been drawn (500 ×) for the development and testing of integrated circuit design and technology.The layout design of devices is based on 10 μm design rules with defined minimum dimensions and clearances in order to avoid the failure of the circuit due to technological inaccuracies. Devices could be easily designed, fabricated and performance evaluated in a fairly good R & D set-up having semiconductor device fabrication facilities.     

The Light-Emitting-Switch Integrated-Circuit Display

A semiconductor display device utilizing arrays of light-emitting devices with inherent memory has been developed. The central element is a p-i-n device that exhibits current-controlled negative resistance and emits light in the high-conductance state. This light-emitting and switching device has been employed in a monolithic integrated circuit that permits the logic function in addition to the opticaf output function to be perfomed on the display surface. The circuit has been developed in a configuration that permits matrix address. This paper discusses the basic light-emitting switch and its utilization as a matrix display device and describes the development of an integrated structure employing the light-emitting switch and its incorporation into a complete display system. Modifications and improvements of the matrix display system based on this concept are also discussed.     

Edge and defect luminescence of powerful ultraviolet InGaN/GaN light-emitting diodes

The spectrum of ultraviolet (UV) InGaN/GaN light-emitting diodes and its dependence on the current flowing through the structure are studied. The intensity of the UV contribution to the integrated diode luminescence increases steadily with increasing density of current flowing through the structure, despite a drop in the emission quantum efficiency. The electroluminescence excitation conditions that allow the fraction of UV emission to be increased to 97% are established. It is shown that the nonuniform generation of extended defects, which penetrate the active region of the light-emitting diodes as the structures degrade upon local current overheating, reduces the integrated emission intensity but does not affect the relative intensity of diode emission in the UV (370 nm) and visible (550 nm) spectral ranges.     

Vacuum-deposited thin-film p-Se/n-CdSe heterojunction diodes

A preliminary feasibility study has been made of vacuum-deposited thin-film diodes based on the p-Se/n-CdSe heterojunction system. These diodes have excellent rectification properties, including: 1) 70-volt reverse breakdown, 2) 10⁵rectification ratio over a range of 25 volts, and 3) 0.5-volt forward offset voltage. The diodes have a "sandwich-cell" structure formed by depositing a CdSe layer onto a Crystallized layer of Se. This work is still in a preliminary stage. However, the results thus far suggest that these diodes may be suitable for use in thin-film integrated circuits for those specialized circuit applications which require only diodes, resistors, and/or capacitors.     

汽车尾灯逻辑检测装置的设计与分析

汽车尾灯系统制作简单,节能可靠,减少交通事故隐患、提高行车的安全性是不懈追求的目标。采用7块集成电路芯片,6个LED发光二极管,4个电阻,2个电容,通过数字逻辑设计的基本方法,设计了一款汽车尾灯系统监测装置,并对汽车尾灯系统的总体设计方案、硬件电路、结构特点、工作原理及其调试方法进行了详细的分析介绍。该系统实现了正常运行、左转、右转、临时刹车等4种常用的汽车尾灯状态,且制作简单,可靠节能,具有比较高的实用价值。     

Three-terminal light-emitting device with adjustable emission color

A three-terminal organic light-emitting device with a periodic interrupted middle electrode is developed to allow for an adjustable emission color. The emission results from three independent light-emitting diodes with one diode utilizing exciplex emission. An equivalent electrical circuit is suggested taking the current–voltage characteristics and the direction of current flow through the organic structure into account. Two diodes are formed between the embedded middle electrode and the LiF/Al top and ITO bottom electrode, respectively, and the third diode utilizes that part of the device without the middle-electrode exhibiting exciplex emission. It will be shown that the spectrum of the emitted light can be tuned from blue to orange by controlling the applied potentials to the device terminals.     

The study of specific features of working characteristics of multicomponent heterostructures and AlInGaN-based light-emitting diodes

Simulation of multicomponent AlInGaN-based heterostructures for their use in light-emitting diodes is performed. The effect of nonuniform distribution of In atoms in the light-emitting “nanodiodes” on the working characteristics of the device in general are determined. A model describing the structure of multicomponent AlInGaN heterostructures for light-emitting diodes is developed.

     

GaP planar monolithic matrix-addressable displays

Display systems that are small in size and require a high density of light-emitting elements can be based on light-emitting diodes. Matrix addressing can be used to minimize the external wires. Interconnections on the display plane can be minimized by the use of a monolithic matrix-addressable display device. A planar processing technique which permits the integration of the light-emitting diode interconnections for a monolithic semiconductor array is presented. The operation of a 5 × 7 monolithic matrix-addressable display device is discussed and demonstrated.     

Highly Crystalline Rubrene Light-Emitting Diodes with Epitaxial Growth

Conventional organic optoelectronic devices suffer from low carrier mobility limited by the static and dynamic disorder. Organic crystals with long-range order can circumvent the effects of disorder and significantly improve the charge transport. While highly ordered organic crystals offer the desirable electronic coupling strength and charge transport, their integration into large-area optoelectronic devices remains a challenge. Here, monolithic integrated triclinic crystal rubrene light-emitting diodes (LEDs) are presented using epitaxial growth with functional additives being engineered into the films. Superior charge transport, excellent operational and long-term stability in these light-emitting devices are demonstrated. By comparing two rubrene-based LEDs, one made from amorphous and one from crystalline rubrene layers, their exciton dynamics are estimated using comprehensive transient electroluminescence simulation. The crystalline LEDs show high triplet-triplet annihilation (TTA) rate constant similar to TTA rate constant of triclinic single crystals determined by optical spectroscopy. At the same time, the crystalline phase enhances drastically the singlet-fission and bimolecular annihilation rates, which reduces the overall performance of the LED compared to its amorphous counterpart. Finally, an outlook on the potential applications of rubrene and/or its derivatives crystalline films are provided for enhancing the performance of organic and hybrid optoelectronic devices.     

Tolerance Design of an Optomechanical Transmitter Assembly for Automotive Applications

We report on different optical coupling concepts between resonant-cavity light-emitting diodes and plastic optical fiber for the automotive according to the Multimedia Oriented Systems Transport standard. We present five different candidate optical coupling schemes. Two coupling schemes were investigated in depth regarding manufacturing and assembly tolerances using a Monte Carlo simulation method: a system using a ball lens and another made by clear molding. We select the best suited system according to manufacturing and assembly capabilities as well as its suitability for automotive applications.      

A thin-film integrated incandescent display

Incandescent alphanumeric displays using a 16-bar format are obtainable today. They employ 1-ml incandescent tungsten helices strung between support posts. This paper describes a new incandescent display device, fabricated by microelectronic thin-film techniques. Such techniques allow high-resolution dot-matrix displays to be produced with all the cost advantages obtained from the employment of modern LSI thin-film processing. The device uses a ceramic substrate covered with a thick layer of glass. Holes are produced in the laminate and filled with metal to eventually form the element support posts. A thin layer of refractory metal is deposited on the glass. The metal and glass are then etched to produce a field of free-standing microfilaments. The resulting display panel can be driven by simple integrated circuits, and the efficiency of the device, operating at 1200°C, is better than quoted for most light-emitting diodes (LED's).     

Improved light coupling efficiency of organic light- emitting diode and polymer optical waveguide integrated device by grating coupler

In this work, the light coupling efficiency of organic light-emitting diode (OLED) and polymer optical waveguide integrated device was improved by the grating coupler. To maximize light coupling efficiency, the grating coupler was optimized by finite-difference time-domain (FDTD) method. Based on the simulation results, the grating coupler was fabricated via laser interference lithography process and an OLED was integrated on the surface of it. Comparing the integrated devices without and with grating coupler, light coupling efficiency of the grating-based integrated device was improved by about 5%. The proposed integrated device has the potential application for low-cost and flexible monolithic optical sensors.     

LED-Based Optical Device for Chronic In Vivo Cerebral Blood Volume Measurement

We demonstrate a reflectivity-based cerebral blood volume sensor comprised of surface-mount light-emitting diodes on a flexible substrate with integrated photodetectors in a form factor suitable for direct brain contact and chronic implantation. This reflectivity monitor is able to measure blood flow through the change of the surface reflectivity and, through this mechanism, detect the cerebral-blood-volume changes associated with epileptic seizures with a signal-to-noise (SNR) response of 42 dB. The device is tested in an in vivo model confirming its compatibility and sensitivity. The data taken demonstrate that placing the sensor into direct brain contact improves the SNR by more than four orders of magnitude over current noncontact technologies.     

Design and fabrication of high-coupling efficiency spot-sizeconverter integrated laser diodes using three-dimensional BMP program

Attention is focused on butt-joint-type spot-size converter integrated laser diodes (SSC-LD's), which allow us to independently optimize the high-temperature performance and coupling efficiency. Increasing the coupling efficiency is achieved by using the three-dimensional (3-D) beam propagation method (BPM). Particular attention is paid to keeping coupling efficiency high, while minimizing variations due to fluctuations in fabrication conditions, such as composition and mesa width. The validity of this method is demonstrated by fabricating a device designed in this way; its coupling efficiency is in excellent agreement with the designed value     

有机白光发光二极管研究进展

有机白光发光二极管是实现全色显示的重要原型器件之一,而且作为一种超薄光源还可用作液晶的背光源以及一些特殊场合的照明.本文从发光区域、器件结构、材料选择等方面回顾了有机白光发光研究的一些进展情况.     

CMOS-compatible organic light-emitting diodes

We report a new method for the integration of light-emitting devices on a silicon substrate. As an active layer, we use unsubstituted PPV or PPV-based organic macromolecules with a p⁺-silicon anode and a cathode made from aluminum or titanium. The polymer is deposited by spin-coating the precursor, followed by a thermal conversion step to form the macromolecules. All process steps, including the possibility of dry etching of the active layer and the upper electrode, are typical for MOS technology. Spectrum analysis, current-voltage, and intensity measurements have been carried out for device characterization. These organic light-emitting diodes allow the monolithic integration of microelectronic circuits and light-emitting devices on one silicon chip applying only typical MOS process steps     

一种新结构LED保护器件的设计研究

针对现有LED旁路保护器件的技术不足,提供了一种低成本但又能满足实际需求的LED局部损坏旁路保护器件的结构。所设计的保护器件集成了晶闸管、电阻及二极管等结构,以四层晶闸管为核心部件,利于提高瞬变电压的耐受能力;在其中增设两个二极管,分别用于调整器件正向工作时的启动电压和为反向工作时提供电流通道。经过流片、封装、测试,获得了主要性能参数。测试结果表明,当正向电压大于4.5V时,器件内部的可控硅结构被触发启动,器件性能符合设计要求。     

发光二极管的低频电容特性

通过自建装置精确测试了发光二极管(LED)的低频(小于102Hz)电学特性。电学测量表明,所有LED在低频下都表现出明显的负电容(NC)现象,且频率越低NC现象越明显。调制发光测量表明,相对发光强度在低频下表现出明显饱和现象,并且随频率增加而减小。比较电学和光学的测量结果可以证实,辐射发光是产生NC现象的主要原因。通过对LED电学测量结果的详细分析得出了NC随电压和频率的变化关系式。