气态源分子束外延InGaP／GaAs结构及其在异质结双极晶体管中的应用

本文研究了ＩｎＧａＰ／ＧａＡｓ异质结构的气态源分子束外延（ＧＳＭＢＥ）生长，所得样品晶格失配率△α／α＜８．９５×１０￣（－５），本底载流子浓度为１０￣（１５）ｃｍ￣（－３）数量级，掺硅ｎ型样品的载流子浓度控制范围可达２×１０￣（１５）～４×１０￣（１８）ｃｍ￣（－３）。研究了Ｐ＿２和Ａｓ＿２气氛的切换条件对ＩｎＧａＰ／ＧａＡｓ异质结构界面特性的影响，并成功地生长了ＩｎＧａＰ／ＧａＡｓ异质结双极晶体管（ＨＢＴ）结构材料，用此材料在国内首次制成的ＨＢＴ器件ｆｒ＝２５ＧＨｚ，ｆ＿（ｍａｘ）＝４６ＧＨｚ，电流增益β＝４０，最高可达β＝１５０。     

AlGaInP/GaAs异质结双极晶体管直流特性研究

制备了大尺寸AlGaInP／GaAs SHBT和DHBT，对其直流特性进行了测试，并分析了AlGaInP／GaA。单异质结晶体管(SHBT)和双异质结晶体管(DHBT)的直流特性差异，深入研究了影响AlGaInP／GaAsHBT开启电压(Voffset)的各个因素。结果表明：AlGaInP／GaAsHBT开启电压与外加基极电流密切相关，采用宽发射区可大大降低器件的开启电压。     

SiGe/Si光电探测器研究进展

本文综述了目前国内外在工作波长１．３～１．５μｍ的ＳｉＧｅ／Ｓｉ超晶格探测器和工作波长为８～１２μｍ的ＳｉＧｅ／Ｓｉ异质结长波长红外探测器方面的研究进展，并分析了存在的问题和材料的各种生长方法。     

SiGe／Si光电探测器研究进展

本文综述了目前国内外在工作波长１．３－１．５μｍ的ＳｉＧｅ／Ｓｉ超晶格探测器的工作波长为８－１２μｍ的ＳｉＧｅ／Ｓｉ异质结长波长红外探测器方面的研究进展，并分析了存在的问题和材料的各种生长方法。     

SiGe/Si异质结光电器件

SiGe/Si异质结光电器件及其光电集成(OEIC)是硅基光电研究的一个非常引人注目的领域.综述了SiGe/Si异质结材料的基本性质,SiGe/Si异质结光电器件的结构、性能、应用及其光电集成.重点介绍了SiGe/Si光电探测器及其与其他相关器件的集成.     

基于高电阻率衬底的Si/SiGe HBT

介绍了一种基于电阻率高达1000Ω·cm的硅衬底的锗硅异质结晶体管的研制.首先根据衬底寄生参数模型分析了衬底对器件高频性能的影响,然后设计了器件的材料与横向结构尺寸,该器件采用掩埋金属自对准技术在3μm工艺线上制备而成,测得其典型直流电流增益为120,BVCEO为9.0V,fT为10.2GHz,fmax为5.3GHz,比同结构尺寸的常规N 衬底Si/SiGe HBT的fT和fmax分别高出3.9GHz和1.5GHz.     

8nm基区宽度负阻双异质结晶体管的设计与研制

本文利用分子束外延(MBE)技术能精确控制外延层厚度的特点,与选择性腐蚀技术相结合,实现了纳米级超薄基区宽度.利用集电极电压VCE调制中性基区宽度可以改变基极电阻,从而产生微分负电阻(NDR),根据这一物理机制,设计并研制成功性能优良的8 nm基区n-InGaP/P+-GaAs/n-InGaP负阻双异质结晶体管(NDRDHBT).该器件显示出基极电压VBE调制的"∧"型负阻集电极电流IC-集电极电压VCE特性,电流峰谷比(PVCR)趋于无穷大;表征基极电压调制电流能力的峰值电流跨导ΔIP/ΔVBE高达11.2 ms;击穿电压达到12 V,可用于高频振荡调制和高速数字电路.     

气态源分子束外延生长重碳掺杂p型InGaAs研究

采用气态源分子束外延(GSMBE)技术,以四溴化碳(CBr4)作为碳杂质源,系统研究了InP衬底上碳掺杂p型InGaAs材料的外延生长及其特性,在AsH3压力5.33×104Pa,生长温度500℃条件下获得了空穴浓度高达1×1020/cm3、室温迁移率为45cm2/Vs的重碳掺杂p型In0.53Ga0.47As材料。研究了CBr4和AsH3束流强度以及生长温度等生长条件对碳掺杂InGaAs外延层组份、空穴浓度和迁移率的影响,并对不同生长条件下的氢钝化效应进行了分析。     

i基区渐变掺杂SiGe/Si异质结开关功率二极管的特性模拟

提出了在SiGe／Si异质结开关功率二极管的本征i区中采用掺杂浓度三层渐变式结构。由Medici模拟所得的特性曲线表明，该结构在正向I—V特性基本不发生改变的前提下，与i区固定掺杂结构相比具有更好的反向恢复电流与反向恢复电压特性，尤其软恢复特性更加明显，反向恢复过程加快。还对渐变掺杂所得到的优越性能进行了分析，从理论上给出了较好的解释。     

低能离子注入对PAn/Si异质结太阳电池的改性研究

利用电化学方法制备了聚苯胺 /Si太阳电池 ,将离子注入改性技术引用到聚苯胺 /Si异质结太阳电池的改性研究中 ,对离子注入后太阳电池顶区材料的吸收光谱和热稳定性能进行了研究 ,测量了改性后电池的输出特性。研究结果表明 :经离子注入改性后的聚苯胺吸收光谱明显变宽 ,材料的热分解温度较注入前提高了 40℃ ,电池在 10 92W/m2 光照时的转换效率提高了 18倍 ,在 37 2W/m2 光照时的转换效率提高了近 3倍     

Arsenic-doped Ge-spiked monoemitter SiGe:C heterojunction bipolar transistors by low-temperature trisilane based chemical vapor deposition

In this work we optimized the Ge-spiked monoemitter for the SiGe:C heterojunction bipolar transistor by using low-temperature trisilane based chemical vapor deposition to meet the requirements of high growth rate and high electrically-active doping levels of arsenic. The resultant devices show improvement of open-base breakdown voltage and no degradation of cutoff frequency with incorporation of a Ge spike in the monoemitter.     

Empirical global modelling of Si/SiGe heterojunction bipolar transistors

A simple and straightforward extraction procedure for a global model of silicon/silicon-germanium (Si/SiGe) heterojunction bipolar transistors (HBTs) is presented. The model has been constructed using functions that describe the dependence of the most nonlinear extracted small-signal equivalent circuit model (SSECM) parameters on the terminal voltages. The other model parameters are assumed to be voltage independent. An artificial neural network fitting tool has been used to obtain these relations. The model has been implemented in a software package without any convergence problems and has been evaluated by direct current, small-signal and large-signal network analyser measurements. An excellent correspondence has been obtained between the measurements and the output of the simulations for the extracted model. Because of its high accuracy, the model is very efficient in radio frequency circuit design. To the author's knowledge, this is the first time that a global model for a Si/SiGe HBT has been derived directly from .a SSECM.     

An a-Si:H/SiGe/Si punchthrough heterojunction phototransistors with an thin-Al film

An a-Si:H/SiGe/Si punchthrough heterojunction phototransistors (PTHPTs), responding to a wavelength of 850 nm, have been proposed and demonstrated in this work. The dramatic difference between PTHPTs and conventional heterojunction phototransistors is that the base is completely depleted in the PTHPTs, thus a larger optical gain is achieved due to the lack of a neutral base. Furthermore, the use of low-temperature a-Si:H instead of conventional crystalline silicon, a strained SiGe can be preserved at the interface of base and emitter, allowing ultrashallow junctions and abrupt doping profiles. Another advantage is that the a-Si:H can provide large valence-band discontinuity between base and emitter, avoiding photogenerated holes injected from base to emitter, and hence a larger collector current. In addition, we employed a thin Al-coating covered on the surface of emitter to enhance the collection of photogenerated holes. In comparison to the PTHPTS without the thin-Al coating, the optical gain of PTHPTs with thin-Al coating is increased from 922 to 3970 at 5-V bias voltage, responding to a light source of 850 nm with 0.028 mW.     

Temperature dependent study on the microwave noise performance of metamorphic InP/InGaAs heterojunction bipolar transistors

In this study, a detailed characterization on the microwave noise performance of high gain metamorphic heterojunction bipolar transistor (MHBT) in the temperature range of 300 K to 380 K is performed. The results are compared between the MHBT and the referenced lattice-matched InP HBT (LHBT) devices. The minimum noise figure (NF_min) versus frequency in the range of 2 to 20 GHz at different temperatures for a 1.6 × 20 μm² HBTs are measured. The experimental results show that the MHBT exhibits a slightly larger variation in NF_min compared to lattice-matched HBTs. Even though the MHBTs may have much higher thermal resistance, this may not significantly affect the device microwave noise performance.     

纳米复合1.4μm光放大材料的荧光和吸收谱

纳米级掺稀土非氧化物团簇复合在氧化硅玻璃中，可以结合非氧化物玻璃和氧化物玻璃在光放大和化学，热力学，力学等方面各自的优点，提供可以应用于实用化1.3μm，宽带1.5μm和新发展的1.4μm光放大的新材料，在一种复合材料中，峰值位于1315nm的荧光峰及线型被证实与用来进行复合的掺稀土氟镓锆玻璃中的峰完全一致，而在复合材料中其荧光寿命较长，以Pr^3 和Nd^3 作为活性离子的复合材料的吸收谱线宽比Pr^3 和Nd^3 掺杂的ZBLAN的相应吸收谱线宽展宽最多达到10nm，复合材料的光谱性质有利于器件增益并放宽对泵浦光源的要求。     

Annealing study of InGaP/GaAs heterojunction bipolar transistor and carbon-doped pGaAs base layers

In this work we have examined the effect of RF annealing (450–750°C, 5–30 min) upon both InGaP/GaAs-based hetero-junction bipolar transistor (HBT) structures, fabricated by metalorganic vapour phase epitaxy (MOVPE), as well as thick carbon (C)-doped p⁺GaAs HBT base layers with varying layer thickness, dopant level and type (intrinsic and extrinsic C precursors) and co-doping (In) strain compensation. Anneal-induced changes in the p⁺GaAs layer lattice strain, Hall carrier concentration and mobility were compared with non-radiative losses, determined from photoluminescence (PL) intensity data. Majority and minority carrier property differences were also compared with IR reflection, Raman backscattering and photoreflectance (PR) data and correlated with changes in MOVPE hydrogen background concentration as determined by secondary-ion-mass-spectroscopy (SIMS). Thick base layer (1.3 μm) HBT structures were also examined for different anneal temperatures and time, showing significant changes in the PR emitter(InGaP)/base (p⁺GaAs) and base/collector (n-GaAs) interface regions for the 650°C anneal condition, as correlated with both PL and SIMS hydrogen concentration data.     

界面自旋翻转对有限尺寸的铁磁体/非磁性半导体/铁磁体体系自旋注入的影响

本文考虑了界面自旋翻转效应后对有限尺寸的铁磁体/非磁性半导体/铁磁体异质结中的自旋注入问题进行了系统的理论探讨.由于自旋在两种介质界面上发生的翻转散射,自旋极化流的每一个分量在界面上都不可能连续.计算结果表明,当自旋注入效率从0增加到100%的过程中,铁磁体/非磁性半导体/铁磁体异质结的隧穿磁阻增大了两个数量级.这一事实证明界面的自旋翻转效应直接影响着铁磁体/非磁性半导体/铁磁体异质结的隧穿磁阻.     

High performance infra-red detectors based on Si/SiGe multilayers quantum structure

Recently, single crystalline (Sc) Si/SiGe multi quantum structure has been recognized as a new low-cost thermistor material for IR detection. Higher signal-to-noise (SNR) ratio and temperature coefficient of resistance (TCR) than existing thermistor materials have converted it to a candidate for infrared (IR) detection in night vision applications. In this study, the effects of Ge content, C doping and the Ni silicidation of the contacts on the performance of SiGe/Si thermistor material have been investigated. Finally, an uncooled thermistor material with TCR of −4.5%/K for 100 μm × 100 μm pixel sizes and low noise constant (K_1/f) value of 4.4 × 10⁻¹⁵ is presented. The outstanding performance of the devices is due to Ni silicide contacts, smooth interfaces, and high quality multi quantum wells (MQWs) containing high Ge content.     

钹式压电复合换能器的有限元分析

主要运用轴对称薄壳截锥单元的有限元分析方法，对钹式压电复合换能器的工作模式进行分析，并计算出在电场的作用下，钹式压电复合换能器的纵向位移，以及纵向位移与端帽及压电陶瓷形状参数的关系，并与试验结果进行对比。