高功率1310nm多量子阱分布反馈激光器

采用金属有机物化学汽相淀积／液相外延生长工艺和多量子阱－分布反馈双沟平面隐埋异质结结构，实现了１３１０ｎｍＩｎＧａＡｓＰ／ＩｎＰ多量子阱分布反馈激光器高功率输出。     

碲锌镉衬底晶面极性对水平液相外延碲镉汞薄膜的影响

研究了碲锌镉衬底（111）晶面的不同极性对水平推舟液相外延生长碲镉汞薄膜的影响。实验结果显示,（111）A面碲锌镉衬底水平液相外延生长碲镉汞薄膜材料组分和厚度均与常规（111）B面碲锌镉衬底碲镉汞薄膜材料相当;碲镉汞母液在采用（111）A面、（111）B面衬底进行液相外延生长的碲镉汞薄膜上接触角分别为（50±2）°和（30±2）°,结合微观模型分析确认碲镉汞母液在碲镉汞薄膜（111）A面存在更大的表面张力;观察并讨论了（111）A面碲镉汞与（111）B面碲镉汞薄膜材料表面微观形貌的差别;实验获得的（111）A面碲镉汞薄膜XRD半峰宽为33.1arcsec。首次报道了（111）晶面选择对母液残留的影响,研究结果表明,采用（111）A面碲锌镉衬底进行碲镉汞水平推舟液相外延生长,能够在不降低晶体质量的情况下,大幅减小薄膜表面母液残留。     

多层液相外延生长器的新结构

下面描述一种用于多层液相外延的石墨舟新结构,这种石墨舟可同时液相外延生长上下两个外延片,下片液相外延是由于活塞将生长溶液从上生长室挤压到下生长室与衬底接触而进行的,上片液相外延是由于上生长室挤压剩余的溶液与衬底相接触而进行的。这种舟的优点是:生长溶液在相当大的过冷度范围内,也可外延生长出光滑平坦的表面,从而改进了外延层的生长质量。在用于双异质结发光管和双异质结激光器的多层外延实验中取得了良好的效果。     

1.3μm波长InGaAsP/InP DC-PBH低阈值激光器的液相外延生长

本文叙述了用于制作1.3μm波长InGaAsP/InP双沟平面隐埋异质结(DC—PBH)激光器的液相外延生长方法,着重讨论了在非平面结构上进行液相外延生长时所遇到的问题及解决措施。采用阳极氧化处理,用InP、Sn合金熔液盖片保护衬底,减少衬底在加热过程申的热损伤等方法获得了高质量的外延片。用该外延片制作的1.3μm波长InGaAsP/InP(DC—PBH)激光器室温连续工作阈值电流最低达9mA,管芯单面输出功率最高达40mW,最高连续激射温度达115℃。     

电流控制LPE生长In_（1－x）Ga_xAs_yP_（1－Y）

用电流控制液相外延（ＣＣＬＰＥ）方法首次在（１００）ＩｎＰ衬底上成功地生长出Ｉｎ１－ｘＧａｘＡｓｙＰ１－ｙ（０．３０＜ｘ＜０．４７，０．７０＜ｙ＜０．９６）外延层，并对外延层特性进行了详细研究，提出在ＩｎＰ衬底上生长电外延层的机理，推导出生长动力学的理论模型，该模型与上述实验结果十分吻合。     

（Hg，Cd）Te薄腰的LPE生长条件与纵向组分分布

根据热力学理论推导出（Ｈｇ，Ｃｄ）Ｔｅ液相外延生长过程中有效分凝系数的表达式并与实验结果进行比较，由此分析了Ｈｇ压、溶液组成、降温速度及过冷度等对（Ｈｇ，Ｃｄ）Ｔｅ液相外延薄膜纵向组分分布的影响．     

1.3微米InGaAsP/InP双沟道平面掩埋异质结激光器

用过冷法两次液相外延生长制作了波长 1.3微米InGaAsP/InP双沟道平面掩埋异质结激光器(DC-PBHLD).室温最低阈值电流15mA,典型值20mA;最高连续工作温度80℃,输出光功率2mW.4倍阈值电流时,仍可得到稳定的单纵模输出.     

1.3μm InGaAsP DCPBH多量子阱激光器

报导了发射波长为1.3μm、具有多量子阱有源层的InGaAsP双沟平面隐埋异质结(DCPBH)激光器制作与性能特征。这些激光器在30℃时阈值电流为40～50mA,外微分量子效率50%,在10～60℃温度范围T。值为160至180K。     

改进碲镉汞液相外延方法原位生长正组分梯度薄膜材料

研究了液相外延生长条件对碲镉汞薄膜材料组分梯度的影响,建立了指导液相外延生长的理论模型。通过改变水平推舟液相外延工艺的汞损失速率,生长出具有正组分梯度的碲镉汞薄膜材料。针对这种特定条件下生长的碲镉汞外延薄膜,通过腐蚀减薄光谱测试与二次离子质谱测试证实了材料具有正组分梯度结构。与传统方法生长的具有负组分梯度的碲镉汞薄膜相比,这种薄膜材料具有相近的表面形貌与红外透射光谱曲线;且具有较高的晶体质量,其X射线衍射双晶摇摆曲线半峰宽达到28.8 arcsec。     

A1_xGa_（1－x）As／GaAs太阳电池的结构观察和器件性能

运用不同的液相外延（ＬＰＥ）生长工艺，制备了两种结构的ＡｌｘＧａ１－ｘＡｓ／ＧａＡｓ太阳电池，并结合透射电子显微镜（ＴＥＭ）等技术分析了外延工艺对器件性能的影响。结果表明，与过冷生长技术相比，回熔工艺对衬底质量的要求不严格，且能形成有利于光生少子被收集的带隙结构。在工艺优化的情况下，我们所获得太阳电池的全面积转换效率在ＡＭ０，１ｓｕｎ条件下为１８．７８％（０．７２ｃｍ２），在ＡＭ１．５，ｌｓｕｎ条件下为２３．１７％。     

Design of quantum well AlGaAs-GaAs stripe lasers for minimizationof threshold current-application to ridge structures

The gain saturation effect and the various leakage currents related to a strip structure (spreading current, lateral diffusion current, optical cavity recombination current, and Auger recombination current) are considered. The minimum threshold current (3.3 mA) is obtained with a multiquantum-well (MQW) structure (5×80 Å) at a cavity length of 80 μm. At these values, the lateral leakage current (spreading and lateral diffusion currents) represents about 50% of the threshold current. It is shown that for short-cavity lasers, the MQW is preferred to the SQW (single-quantum-well) structure. However, the well number in the active layer of a ridge structure is limited by the decrease of the parallel confinement and the increase of the lateral leakage current. Finally, good agreement was obtained in comparing the calculations with experimental results for GRINSCH (graded-index separate-confinement heterojunction) SQW lasers     

一种低失调高压大电流集成运算放大器

基于结型场效应晶体管(JFET)和双极型晶体管(BJT)兼容工艺,设计了一种低失调高压大电流集成运算放大器。电路输入级采用p沟道JFET (p-JFET)差分对共源共栅结构;中间级以BJT作为放大管,采用复合有源负载结构;输出级采用复合npn达林顿管阵列,与常规推挽输出结构相比,在输出相同电流的情况下,节省了大量芯片面积。基于Cadence Spectre软件对该运算放大器电路进行了仿真分析和优化设计,在±35 V电源供电下,最小负载电阻为6Ω时的电压增益为95 dB,输入失调电压为0.224 5 mV,输入偏置电流为31.34 pA,输入失调电流为3.3 pA,单位增益带宽为9.6 MHz,具有输出9 A峰值大电流能力。     

GaAs/AlGaAs quantum well infrared photodetector with low noise

A novel kind of multi-quantum well infrared photodetector（QWlP） is presented. In the new structure device,a p-type contact layer has been grown on the top of the conventional structure of QWlP,then a small tunneling current is instead of the large compensatory current,which made the device low dark current and low noise characteristics. The measured result of dark current is consistent with the calculated result, and the noise of the new structure QWIP is decreased to one third of the conventional QWlP.     

Dual MOS gate controlled thyristor (DMGCT) structure withshort-circuit withstand capability superior to IGBT

A dual MOS gate controlled thyristor (DMGCT) structure is analyzed with experimental data and shown to have superior performance over insulated-gate bipolar transistor (IGBT) for power switching applications. The DMGCT device structure consists of a thyristor structure with the thyristor current constrained to flow via the channel region of a MOSFET. Although this increases the on-state voltage drop in the thyristor current path by a small amount due to the voltage drop across the low-voltage series MOSFET, this structure allows control of the thyristor current by the gate voltage applied to the MOSFET even after latch-up of the thyristor. This configuration allows uniform turn-off in the device with no current crowding. The DMGCT does not have any parasitic thyristor structure. In contrast to the IGBT, the saturation current of the DMGCT can be controlled independently of the on-state voltage drop     

高亮度LED芯片的反射型电流阻挡层设计与实现

基于光学传输理论矩阵,设计制作SiO2和Ti3O5交替生长的分布式布拉格反射(DBR)结构作为LED芯片的电流阻挡层,并采用电感耦合等离子体(ICP)刻蚀技术在电流阻挡层处形成沟槽结构,以解决困扰LED器件效率提高的电流扩散及金属电极降低出光效率的问题。实验结果表明,采用这种结构的LED芯片能将亮度提高5%以上,而LED芯片的正向电压基本维持不变。这种反射型电流阻挡层结构能够很好地改善大尺寸LED芯片的电流扩散,有效地提高LED芯片的出光效率。     

A novel 4H-SiC MESFET by lateral insulator region to improve the DC and RF characteristics

In this paper, a novel recessed gate metal–semiconductor field-effect transistor (RG-MESFET) is presented by modifying the depletion region and the electric field. The proposed structure improves the breakdown voltage, drain current and high frequency characteristics by embedding a lateral insulator region between drain and gate while is placed laterally into the metal gate and a silicon well exactly under the insulator region. We called this new structure as modified recess gate MESFET (MRG-MESFET). The radio frequency and direct current (DC) characteristics of the proposed structure is studied using numerical simulations and compared with a conventional MESFET (C-MESFET). The breakdown voltage, drain current DC transconductance and maximum power density of the proposed structure increase by 27%, 16.5%, 15% and 48%, respectively, relative to the C-MESFET. Also, the gate-source capacitance and the minimum noise figure of the proposed structure improve relative to the C-MESFET. The proposed structure can be used for high breakdown voltage, high saturation drain current, high DC transconductance, high power, high frequency, and low noise applications.     

应用EBG结构抑制电磁干扰的研究

电磁带隙结构(EBG)是一种周期性结构,具有明显的带阻特性。首先介绍了EBG结构的特点,通过理论分析计算和仿真,阐述了其禁带形成的原因,依据EBG结构所具有性质的特点,分析了该结构对表面电流的影响。并利用EBG结构带阻特性以及影响表面电流的特性,将其应用于抑制表面电流从而减小电磁干扰(EMI)。通过仿真建模实验、数据测量得到的结果,说明了将EBG结构应用于抑制电磁干扰的可行性。     

ITO像素电极工序对于HADS产品TFT特性的影响

通过不同TFT几何结构验证ITO像素电极工序对于HADS产品TFT特性的影响。实验结果显示TN5mask与倒反HADS结构(源漏极→ITO像素电极)二者有比现行HADS结构(ITO像素电极→源漏极)更高的Ion,提升比率达到40%。推测主要原因为现行HADS结构(ITO像素电极→源漏极)在Si岛完成后进行ITO像素电极工序增加了N+与源漏极之间接触阻抗导致Ion降低。对于HADS产品,倒反HADS结构(源漏极→ITO像素电极)可以具有更好的TFT特性表现。对现行HADS结构,在沟道形成工序前的N+表面ITO残沙程度越少则Ioff越低;对于倒反HADS结构,沟道形成之后沟道表面ITO残沙程度对则对TFT特性没有明显影响。对于Poole-Frenkel区域,现行HADS结构(ITO像素电极→源漏极)比TN5mask与倒反HADS结构(源漏极→ITO像素电极)二者较低Ioff[Vg=-20V],下降达50%,主要为N+与源漏极之间接触阻抗增加的影响。     

Feasibility of substrate fed threshold logic

Proposes a modified integrated injection logic (I/SUP 2/L) structure called substrate fed threshold logic (SFTL) for the implementation of multivalued logic. In this structure, threshold current is supplied from the p/SUP +/ substrate to the top p region through the windows in the n/SUP +/ buried layer, and the magnitude of the threshold current is determined by the number of injection windows. The feasibility of the structure is discussed theoretically and experimentally. The results show that four-valued threshold logic is possible with the proposed structure.     

32×32双色红外探测器同步读出电路设计

双色（中短波）同步工作模式的红外探测器,其输出光电流信号为中波信号和中短波混合信号。文中提出了一种电压信号相减的电路结构,可在中波和中短波信号同步积分后,将两个波段的积分电压信号进行相减,得到单独的短波信号,实现信号分离的过程,并对32×32规模的电路进行了仿真验证,电路在仿真中有良好的性能。