MSM7512B与标准Modem建立连接

探讨MSM7512B遵从ITU-TV.23规范,以主叫和被叫方式与标准Modem（如Hayes的AT指令集兼容的Modem)建立连接的方法和实现过程。     

10 Gb/s OEIC optical receiver front-end and 3.125 Gb/s PHEMT limiting amplifier

A 10 Gb/s OEIC (optoelectronic integrated circuit) optical receiver front-end has been studied and fab ricated based on the φ-76 mm GaAs PHEMT process; this is the first time that a limiting amplifier (LA) has been designed and realized using depletion mode PHEMT. An OEIC optical receiver front-end mode composed of an MSM photodiode and a current mode transimpedance amplifier (TIA) has been established and optimized by simu lation software ATLAS. The photodiode has a bandwidth of 10 GHz, a capacitance of 3 fF/μm and a photosensitive area of 50×50 μm~2. The whole chip has an area of 1511×666 μm~2. The LA bandwidth is expanded by spiral inductance which has been simulated by software HFSS. The chip area is 1950×1910μm~2 and the measured results demonstrate an input dynamic range of 34 dB (10-500 mVpp) with constant output swing of 500 tnVpp.     

94K低温下和室温下GaN基MSM紫外光探测器性能的比较

在采用MOCVD技术生长的GaN膜上制备出MSM紫外光探测器，分别在室温下和94K低温下，测量了探测器对不同光波长的响应、同一光波长下对不同偏压的响应、不同斩波频率下的响应。结果表明，在94K下响应有了很大的改善。当光波长从360nm增加到450nm时，响应下降了3个数量级，而常温下只下降两个数量级，但探测器的时间响应常数变长了。     

Characterization of dark noise in CdZnTe spectrometers

Systematic measurements of dark noise spectra of CdZnTe x- and γ-ray spectrometers, correlated with the dc I-V characteristics and detector technology, are reported. The dark noise of two innovative CdZnTe spectrometer configurations are studied: metal-semiconductor-metal (MSM) resistive detectors with three terminals as well as heterostructure PIN detectors with thermally evaporated n⁺ CdS and p⁺ ZnTe contacts, which are fabricated on high pressure Bridgman CdZnTe (Zn=10%) crystals. The two innovative CdZnTe spectrometer configurations presented here exhibit very low dark (leakage) current. By reducing the dc value of the dark (leakage) current below 1 nA, shot noise becomes the dominant noise mechanism and the contribution of 1/f noise becomes negligible. The use of non-injecting contacts (evaporated gold) for the MSM detectors and the operation of the PIN detector in the reverse bias mode prevent generation-recombination noise which becomes dominant with injecting contacts (for example MSM detectors with evaporated indium and titanium contacts) or when operating the PIN detector in the forward bias mode. Surface leakage is reduced by applying surface passivation but is eliminated only by using the three terminal MSM configuration which exhibits simple shot noise instead of the suppressed shot noise observed in the two terminal MSM spectrometers. The noise measurements are useful for optimizing detector technology.     

TiO2薄膜紫外探测器的光电特性

采用溶胶-凝胶法（Sol-Gel），在Si衬底上生长了TiO2纳米薄膜，并用此材料制备了光电导型的TiO2薄膜紫外光探测器．通过测量探测器的光电流与照射光波长的关系，可以看出，TiO2探测器在紫外波段230～280nm有很明显的光响应，光电流谱线近乎平坦；在280nm处光响应出现明显下降，且跨度较大，直至360nm又再次趋于平坦．测量了250nm波长处的响应度和外加偏压的关系，发现响应度随外加偏压的增加而增加，5V时达到饱和．     

异质结光电探测器的性能研究

光电探测器用于将光纤传输的光信号转变为电信号,是半导体光电子学的重要器件。本文主要介绍几种异质结光电探测器的器件结构和工作原理,旨在探讨异质结光电探测器的研究现状和发展趋势。     

10Gb/s OEIC光接收机前端及3.125Gb/s限幅放大器

摘要：基于南京电子器件研究所Φ76mm GaAs pHEMT工艺,研制了10Gb/s OEIC光接收机前端,并首次采用耗尽型PHEMT设计并实现了限幅放大器。借助模拟软件ATLAS建立并优化了器件模型,组成形式为MSM光探测器和电流模跨阻放大器,探测器带宽超过10GHz,电容约3fF/μm,光敏面积50×50μm2,整个芯片面积1511μm×666μm。限幅放大器采用无源电感扩展带宽,并借助三维电磁仿真软件HFSS进行模拟仿真。限幅放大器芯片面积1950μm×1910μm,在3.125Gb/s传输速率下,分别输入10mVpp和500mVpp,可以得到500mVpp恒定输出摆幅。     

Simulation and optimization of a 6H-SiC metal-semiconductor-metal ultraviolet photodetector

正Based on thermionic emission theory,a model of a 6H-SiC metal-semiconductor-metal(MSM) ultraviolet photodetector is established with the simulation package ISE-TCAD.A device with 3μm electrode width(W) and 3μm electrode spacing(L) is simulated.The findings show that the MSM photodetector has quite a low dark current of 15 pA at 10V bias and the photocurrent is two orders of magnitude higher than the dark current.The influences of different structures on dark and illuminated current-voltage characteristics of the MSM photodetector are investigated to optimize the device parameters.Simulation results indicate that the maximum photocurrent and the highest ratio of photocurrent to dark current at 15 V bias are 5.3 nA and 327 with device parameters of W=6μm,L=3μm and W =3μm,L=6μm,respectively.     

Simulation and optimization of a 6H-SiC metal-semiconductor-metal ultraviolet photodetector

Based on thermionic emission theory,a model of a 6H-SiC metal-semiconductor-metal (MSM) ultraviolet photodetector is established with the simulation package ISE-TCAD.A device with 3μm electrode width (W) and 3μm electrode spacing (L) is simulated.The findings show that the MSM photodetector has quite a low dark current of 15 pA at 10 V bias and the photocurrent is two orders of magnitude higher than the dark current.The influences of different structures on dark and illuminated current-voltage characteristics of the MSM photodetector are investigated to optimize the device parameters.Simulation results indicate that the maximum photocurrent and the highest ratio of photocurrent to dark current at 15 V bias are 5,3 nA and 327 with device parameters of W = 6μm,L=3μm and W =3μm,L = 6μm,respectively.     

多晶Ni-Mn-Ga磁性记忆合金的相变行为及稀土元素铽的作用

研究了Ni50Mn25 xGa25-x 和Ni50Mn29Ga21-xTbx 2种成分系列磁性记忆合金的相变行为. 保持Ni含量不变, 增加Mn, 降低Ga含量会使马氏体相变温度明显提高, 同时相变滞后温区减小, 居里温度基本不变. 如果添加稀土元素铽, 相变温度继续升高, 居里温度仍然不变, 材料继续保持强的铁磁性及热弹性马氏体相变的特征.