320 × 240 CMOS array for the spectral range of 3–5 μm based on PtSi photodiodes

The results of research and development of a 320 × 240 platinum silicide focal plane array (FPA) for the spectral range of 3–5 μm are presented. The development is based entirely on CMOS technology. It is shown that the FPA makes it possible to adjust the photosignal accumulation time at a fixed frame rate and subtract the background constant component in the output device.     

High-speed photodiodes for the mid-infrared spectral region 1.2–2.4 μm based on GaSb/GaInAsSb/GaAlAsSb heterostructures with a transmission band of 2–5 GHz

High-speed p-i-n photodiodes for the spectral range of 1.2–2.4 μm are fabricated for the first time based on a GaAs/GaInAsSb/GaAlAsSb heterostructure with separated sensitive-(50 μm in diameter) and contact mesas, which are connected by a bridge front contact. The use of an unconventional design for the contact mesa with a Si₃N₄ insulating sublayer 0.3 μm thick under the metal contact made it possible to lower both the intrinsic photodiode capacitance and the reverse dark currents. The photodiodes have a low intrinsic capacitance of 3–5 pF at zero bias and 0.8–1.5 pF at a reverse bias of 3.0 V. The photodiode operating speed, which is determined by the time of increasing the photoresponse pulse to a level of 0.1–0.9, is 50–100 ps. The transmission band of the photodiodes reaches 2–5 GHz. The photodiodes are characterized by low reverse dark currents I _d = 200–1500 nA with a reverse bias of U = ?(0.5–3.0) V, a high current monochromatic sensitivity of R _i = 1.10–1.15 A/W, and a detectability of D*(λ_max, 1000, 1) = 0.9 × 10¹¹ W^?1 cm Hz^1/2 at wavelengths of 2.0–2.2 μm.     

IR photodetectors in the range of λ = 1.5–8 μm, based on silicon with multicharged nanoclusters of manganese atoms

It is demonstrated that infrared photodetectors based on silicon with multicharged nanoclusters of manganese atoms can be designed that operate in the wavelength range of ?? = 1.55?C8 ??m. Photodetectors fabricated on such materials have the following parameters: a spectral sensitivity range of ?? = 1.55?C8 ??m, an operating temperature range of T = 77?C250 K, an optimal electric field of E = 5 V/cm, an optimal size of V = 3 × 2 × 1 mm³, a sensitivity threshold of S = 10^?9 W/cm², and a response time of ?? < 10^?6 s.     

Direct calculations on the band offsets of large-lattice-mismatched and heterovalent Si and Ⅲ-Ⅴ semiconductors

Band offset in semiconductors is a fundamental physical quantity that determines the performance of optoelectron-ic devices.However,the current method of calculating band offset is difficult to apply directly to the large-lattice-mismatched and heterovalent semiconductors because of the existing electric field and large strain at the interfaces.Here,we proposed a modified method to calculate band offsets for such systems,in which the core energy level shifts caused by heterovalent ef-fects and lattice mismatch are estimated by interface reconstruction and the insertion of unidirectional strain structures as trans-itions,respectively.Taking the Si and Ⅲ-Ⅴ systems as examples,the results have the same accuracy as what is a widely used method for small-lattice-mismatched systems,and are much closer to the experimental values for the large-lattice-mis-matched and heterovalent systems.Furthermore,by systematically studying the heterojunctions of Si and Ⅲ-Ⅴ semiconduct-ors along different directions,it is found that the band offsets of Si/lnAs and Si/lnSb systems in[100],[110]and[111]direc-tions belong to the type I,and could be beneficial for silicon-based luminescence performance.Our study offers a more reli-able and direct method for calculating band offsets of large-lattice-mismatched and heterovalent semiconductors,and could provide theoretical support for the design of the high-performance silicon-based light sources.     

Design of airport wake vortex monitoring system based on 1.5-μm pulsed coherent Doppler lidar

To shun the vortex hazard,the airport wake vortex monitoring system based on 1.5-mm pulsed coherent Doppler lidar is designed successfully in this paper.Based on the realistic analytical model,the wake vortex generated by airbus A340 under typical flight condition is simulated.Then the principle of airport wake vortex monitoring is introduced,and the work flow of the monitoring system is also presented.Moreover,based on the mechanism of vortex coherent detection and typical system parameters,both detection SNR and detection precision are obtained through numerical simulations.When the system outputs 2 J energy,the coherent detection SNR at 10 km distance is up to 23.452,and detection precision can reach 0.328 m/s.With the wake vortex monitoring experiment of A340,some vortex parameters are estimated.Due to these results comparatively coinciding with the previous simulation conclusions,the ability of Doppler lidar for full-scale wake vortex characterization and real time measurement is demonstrated.The study shows that the wake vortex detection based on 1.5-mm pulsed coherent Doppler lidar has the advantages of high accuracy and far distance,and the designed airport wake vortex monitoring system has proved to be effective and feasible,which has significant development and application prospect in the aspect of assuring flight security and increasing airport capacity.     

High-temperature(T = 80℃) operation of a 2μm InGaSb-AlGaAsSb quantum well laser

正An InGaSb/AIGaAsSb compressively strained quantum well laser emitting at 2μm has been fabricated. An output power of 82.2 mW was obtained in continuous wave(CW) mode at room temperature.The laser can operate at high temperature(T = 80℃),with a maximum output power of 63.7 mW in CW mode.     

Calculation of the Schottky barrier and current–voltage characteristics of metal–alloy structures based on silicon carbide

A simple but nonlinear model of the defect density at a metal–semiconductor interface, when a Schottky barrier is formed by surface defects states localized at the interface, is developed. It is shown that taking the nonlinear dependence of the Fermi level on the defect density into account leads to a Schottky barrier increase by 15–25%. The calculated barrier heights are used to analyze the current–voltage characteristics of n-M/p-(SiC)_1–x(AlN)_x structures. The results of calculations are compared to experimental data.     

Switching of the photonic band gap in three-dimensional film photonic crystals based on opal-VO<Subscript>2</Subscript> composites in the 1.3–1.6 μm spectral range

The parameters of three-dimensional photonic crystals based on opal-VO₂ composite films in the 1.3–1.6 μm spectral range important for practical applications (Telecom standard) are numerically calculated. For opal pores, the range of filling factors is established (0.25–0.6) wherein the composite exhibits the properties of a three-dimensional insulator photonic crystal. On the basis of the opal-VO₂ composites, three-dimensional photonic film crystals are synthesized with specified parameters that provide a maximum shift of the photonic band gap in the vicinity of the wavelength ∼1.5 μm (∼170 meV) at the semiconductor-metal transition in VO₂.     

Mechanisms of homo- and heteroepitaxial growth of SiC on α-SiC(0001) by solid-source molecular beam epitaxy

Epitaxial growth of SiC on hexagonal (or α)-SiC(0001) has been performed by means of solid-source molecular beam epitaxy (MBE). The solid-source MBE growth conditions have been analyzed concerning the supersaturation and the excess phase formation of silicon and carbon. In general, our results demonstrate that control of the Si/C ratio and the supersaturation (S) is essential for the growth mode and the kind of polytype grown. Low temperature (T<1450K) deposition on on-axis SiC substrates always results in the growth of 3C-SiC, which is significantly improved by an alternating supply of Si and C. On vicinal substrates, a step flow growth mode has been realized at T down to 1300K. In experiments performed at T>1450K under near surface equilibrium conditions, different growth modes, and conditions stabilizing the growth of certain polytypes have been found. With a step decrease of S, a step-flow growth mode of both 4H-and 6H-SiC was obtained and, for the first time in case of epitaxial SiC growth, a homogeneous nucleation of α-SiC at more C-rich conditions has been realized. Conditions stabilizing the growth of certain polytypes have been estimated by thermodynamic calculations considering the influence of polytype structure on the supersaturation and the surface energy. Based on these results, we have demonstrated the growth of a double-heterostructure by firstly growing a 3C-SiC layer on 4H-SiC(0001) at low temperature and a subsequent growth of 4H-SiC under near surface equilibrium conditions on a C-stabilized surface on top of this layer.     

Photosensitivity of thin-film structures based on (CuInSe2)x(2ZnSe)1−x solid solutions

Polycrystalline (CuInSe₂)_x(2ZnSe)_1−x films (x=0.6–1.0) with p-type conductivity and a thickness of 0.5–0.9 μm were obtained by pulsed laser evaporation. It is shown that a chalcopyrite-sphalerite transition occurs in the above system for x=0.7. The obtained films were used to fabricate the photosensitive structure of the In/p-(CuInSe₂)_x(2ZnSe)_1−x and InSe(GaSe)/(CuInSe₂)_x(2ZnSe)_1−x types. Spectral dependences of photovoltaic-conversion quantum efficiency were studied, and the photosensitivity of the structures in relation to the type of energy barrier and the composition was analyzed. It is concluded that the structures under consideration can be used as broadband photovoltaic converters. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 34, No. 5, 2000, pp. 576–581. Original Russian Text Copyright ? 2000 by V. Rud’, Yu. Rud’, Bekimbetov, Gremenok, Bodnar’, Rusak.     

Design and experimental analysis of fiber grating vibration demodulation system based on the 3 × 3 coupler

A novel fiber grating vibration demodulation system, based on 2×2 and 3×3 couplers, is designed. Based on the phase unwrapping algorithm, the three-way asymmetrical output of the 3×3 coupler and demodulation state characteristics of the system when the vibration signal includes high harmonic waves are analyzed in simulations. The result shows that when the three-way output is asymmetrical, the maximum deviation of demodulation signal is 1.625%, and when the vibration signal includes high harmonic waves, the maximum deviation of demodulation signal is 0.9%. The corresponding experiment is conducted. The experimental result shows that the dynamic resolution of the system is 25.22 nɛ / $ \sqrt {Hz} $ \sqrt {Hz} when the vibration pitch is 5.5 Hz.     

Maskless selective area growth of InP on Sub-μm V-groove patterned Si(001)

Low pressure metalorganic chemical vapor deposition of InP onexactly oriented Si(OOl) substrates with a periodic V-groove pattern of periodicity ≤1.2 μm using a two temperature growth sequence (400 and 640°C) is reported. Planar InP layers with extremely low defect density of 7 × 10⁴ cm⁻² are obtained. For InP on V-grooves of width g ≤1.0μm, a planar surface is formed after less than 1 μm of growth. Formation or suppression of antiphase domains (APDs) is a function of the widths of the (OOl)-oriented ridges. For s ≤1 μm, epilayers are single domain and the direction is oriented parallel to the grooves. At 400°C, nucleation starts homogeneously on {111}-sidewallsand (001)-facets. While heating up to 640°C, InP migrates into the grooves, depleting almost completely the (001)-facets. During growth of the main layer, first the V-grooves are filled up. Subsequently (001)-ridges are overgrown laterally or voids are formed on top of them. This mechanism is responsible for both planarization and APD-suppression. The surface migration length of InP on Si(001) at 640°C is estimated to be ≈0.5 μm.     

UHF RF Front-End Circuits in 0.35-μm Silicon on Insulator (SOI) CMOS

In this work, design and measurement results of UHF RF frontend circuits to be used in low-IF and subsampling receiver architectures are presented. We report on three low noise amplifiers (LNA) (i) single-ended (ii) differential (iii) high-gain differential and a double-balanced mixer all implemented in 0.35-μ m SOI (Silicon on Insulator) CMOS technology of Honeywell. These circuits are considered as candidate low-power building blocks to be used in the two fully-integrated receiver chips targeted for deep space communications. Characteristics of square spiral inductors with high quality (Q) factors (as high as 10.8) in SOI CMOS are reported. Single-ended and fully-differential LNA's provide gains of 17.5 dB and 18.74 dB at 435 MHz, respectively. Noise figure of the single-ended LNA is 2.91 dB while the differential LNA's noise figure is 3.25 dB. These results were obtained for the power dissipations of 12.5 mW and 16.5 mW from a 2.5-V supply for the single-ended and differential LNA's, respectively. High-gain low-power differential LNA provides a small-signal gain of 45.6 dB with a noise figure of 2.4 dB at 435 MHz. Total power dissipation of the high gain LNA is 28 mW from a 3.3-V supply. The double-balanced mixer provides a conversion gain of 5.5 dB with a noise figure of 13 dB at 2 MHz IF. The power dissipation of the mixer is 11.5 mW from a 2.5-V supply. The measured responses and the power dissipations of the building blocks meet the requirements of the communications system. The die areas occupied by the single-ended LNA, differential LNA, high-gain LNA and the mixer are 0.6 mm × 1.4 mm, 1 mm × 1.4 mm, 1.4 mm × 1.2 mm and 0.6 mm × 0.9 mm, respectively. Ertan Zencir received the B.Sc. and M.S. degrees in electrical and electronics engineering from Middle East Technical University, Ankara, Turkey, and Ph.D. degree in electrical engineering from Syracuse University, Syracuse, NY in 1995, 1997, and 2003, respectively. He joined the Electrical Engineering and Computer Science Department of University of Wisconsin-Milwaukee as an Assistant Professor in August 2004. 2003). His current research focuses on RFIC and transceiver design for wireless communications. Douglas Te-Hsin Huang was born in Chia-yi Taiwan. He received the B.S. degree in electrical engineering from National Taiwan Ocean University, Kee-lung, Taiwan in 1993, and the M.S. and Ph.D. degrees in electrical engineering from Syracuse University, Syracuse, New York, in 2001 and 2003, respectively. In 2004, he joined Skyworks Solutions Inc., where he is currently an RFIC Design Engineer. His research deals mainly with low-power, infrastructure, analog RFIC, and microwave integrated circuit designs. Besides microwave and semiconductor engineering, Dr. Huang has broad interest in art, music, and philosophy. Ahmet Tekin received his B.S. degree in Electrical Engineering from Bogazici University, Istanbul, Turkey in 2002 and MS degree in Electrical engineering form North Carolina A&T State University, Greensboro, NC. He is currently working towards his PhD degree at University of California, Santa Cruz, CA. He was a Research Assistant at RF Microelectronic Laboratory, North Carolina A&T State University, from 2002 to 2004. He worked on the design of low power UHF transceiver circuits for space applications. He is currently a Research Assistant at Bio-mimetic Microelectronic Systems Laboratory, University of California at Santa Cruz, working on implantable very low power UHF frequency transceiver for a body sensor network. Numan S. Dogan received the B.Sc. degree from Karadeniz Technical University, Trabzon, Turkey, in 1975, the M.Sc. degree from Polytechnic University, New York, in 1979, and the PhD degree from the University of Michigan, Ann Arbor, in 1986, all in electrical engineering. Since 1998, he has been with the Electrical and Computer Engineering Department, North Carolina A&T State University, Greensboro, North Carolina, where he is an Associate Professor. He was a Visiting Faculty Researcher at Air Force Research Laboratory (AFRL), Eglin Air Force Base, Florida, in 1998, and General Electric Corporate Research and Development Laboratory, Schenectady, New York, in 1999. His earlier research interests included microwave and millimeter-wave solid-state devices and circuits, high-temperature electronics, and silicon micromachining. His recent research interests include RF CMOS Integrated Circuits and low-power Medical Implant Communication Systems (MICS) transceivers. Currently he serves as the Chair of the IEEE Central North Carolina Section. In April 2004, he organized “a walking robot competition” for High School Students. He enjoys hiking to Alpine Lakes in the Pacific Northwest and fishing. Ercument Arvas (M'85–SM'89) received the B.S. and M.S. degrees from METU, Ankara, Turkey, in 1976 and 1979, respectively, and the Ph.D. degree from Syracuse University, Syracuse, New York, in 1983, all in Electrical Engineering. Between 1984 and fall of 1987, he was with the Electrical Engineering Department of Rochester Institute of Technology, Rochester, New York. He joined the Electrical Engineering and Computer Science Department of Syracuse University in 1987, where he is currently a Professor. His research interests include numerical electromagnetics, antennas, and microwave circuits and devices.     

高分辨率中红外遥感(3～5μm)成像模拟中邻近效应分析

在星载高分辨率遥感成像模拟中,需要重点考虑大气辐射传输过程.通常情况下,中红外波段大气多次散射作用可以忽略,但在高分辨率中红外遥感成像中却需对由多次散射产生的邻近效应加以适当考虑.为对其进行定量分析,分别将影响中红外邻近效应的地表、大气及卫星观测几何参量等进行分析,结果表明:邻近效应随像元测量条件而改变,且在正常条件下其贡献达到3%左右.通过将现有大气点扩散函数(PSF)解析算法扩展至中红外波段,建立了中红外像元邻近效应模型,将其与大气辐射传输模型进行耦合,共同实现大气辐射传输与邻近效应模拟.模拟结果表明,模型是正确的,且应用方法切实可行;对中红外大气校正、成像模拟均具有一定参考价值.     

3～5μm稀土离子掺杂中红外光纤激光器的研究进展(特邀)

3～5μm中红外波段是一个极特殊的电磁波谱区间,它不仅覆盖着众多分子与原子的本征吸收峰,同时还是大气透明窗口之一。此波段的激光器在气体探测、生物医疗、国防等众多领域都具有很大的应用前景。文中围绕常用于3～5μm光纤激光产生的三种稀土离子(即Er³⁺、Ho³⁺和Dy³⁺),对基于这些离子掺杂的连续和脉冲中红外光纤激光器的发展现状进行了梳理,最后对3～5μm掺稀土离子光纤激光器的发展进行了展望。     

Improvement of the Q-factor,for an adjustable inductor using a 90-μm silicon substrate on plastic

This article presents a four-port adjustable inductor with 0.18?µm Complementary Metal-Oxide-Semiconductor (CMOS) technology on plastic. The inductor has a high Q-factor and a small size for multiband UWB applications. When the four-port adjustable inductor, on VLSI-standard Si substrate, operates near 3, 4, 7.5 and 9?GHz, it has a Q-factor of 6.5, 6.7, 8 and 11.5 and an inductance of 2.1, 1.6, 1.1, 0.6?nH, respectively. Reducing the thickness of the Si substrate to 90?µm and mounting it on plastic causes a 25–31% improvement in the Q-factor, without change in the inductance, due to a reduction in the parasitic effect from the Si substrate. This is useful for multiband applications.     

Evaluation of RF electrostatic discharge (ESD) protection in 0.18-μm CMOS technology

Electrostatic discharge (ESD) protection design is challenging for RF integrated circuits (ICs) because of the trade-off between the ESD robustness and parasitic capacitance. ESD protection devices are fabricated using the 0.18-μm RF CMOS process and their RF ESD characteristics are investigated by the transmission line pulsing (TLP) tester. The results suggest that the silicon controlled rectifier (SCR) is superior to the diode and NMOS from the perspective of ESD robustness and parasitic, but the SCR nevertheless possesses a longer turn-on time.     

Design and verification of a 10-bit 1.2-V 100-MSPS D/A IP core based on a 0.13-μm low power CMOS process

Based on a low supply voltage curvature-compensated bandgap reference and central symmetry Q~2 random walk NMOS current source layout routing method,a 1.2-V 10-bit 100-MSPS CMOS current-steering digital-to-analog converter is implemented in a SMIC 0.13-μm CMOS process.The total consumption is only 10 mW from a single 1.2-V power supply,and the integral and differential nonlinearity are measured to be less than 1 LSB and 0.5 LSB, respectively.When the output signal frequency is 1-5 MHz at 100-MSPS samplin...     

Effect of Ultraviolet Radiation and Electric Field on the Conductivity of Structures Based on α- and ε-Ga2O3

Semiconductors - The effect of ultraviolet radiation and a strong electric field on the conductivity of structures based on two types of polymorphic gallium-oxide films is studied. Both types of...