P－GaP中离子注入缺陷的形成

研究了Ｚｎ~＋离子注入ｐ－ＧａＰ半导体所引起的缺陷。在电流密度为０．０３μＡ／ｃｍ~２下，将注入Ｚｎ~＋离子剂量为１×１０１~（１４）离子／厘米~２的ＧａＰ样品腐蚀出蚀坑后用ＳＥＭ观察，结果表明，在离子注入区域有缺陷形成。     

Ti3Al-Nb合金不同组织状态下的室温拉伸变形机制

在扫描电镜和Ｈ－８００透射电子显微镜上，研究了Ｔｉ３Ａｌ－Ｎｂ（Ｔｉ－２４Ａｌ－１４Ｎｂ－３Ｖ－０．５Ｍｏ）（ａｔ．％）合金不同组织状态下的室温拉伸变形机制。利用双倾技术和双束条件下ｇ．ｂ＝０不可见判据，分析了合金中具有Ｄ０１９结构的α２相和ｂｃｃ结构的Ｂ２相在拉伸变形后的位错类型和滑移系。结果表明，初生α２相体积分数高时，α２相内部出现致密且平行的滑移带，ａ型位错在基面｛０００１｝上形成大量亚晶界和六角位错网络，使初生α２晶粒产生形变，并且协调了晶界的变形。另外，还有ａ型刃位错及少量ｃ型位错在柱面｛１０１０｝上滑移，初生α２相体积分数低时，基体Ｂ２相上形成宽而长的滑移带，ａ／２〈１１１〉刃型位错在｛１１０｝面上滑移是Ｂ２相的主要变形模式。     

工艺因素对Ba_(6-3x)(Sm_(1-y)Nd_y)_(8+2x)Ti_(18)O_(54)陶瓷微波特性的影响

探讨了研磨时间，黏合剂浓度、用量，压力，保压时间，预烧温度，烧结温度，烧结时间等工艺因素对Ｂａ６－３ｘ（Ｓｍ１－ｙＮｄｙ）８＋２ｘＴｉ１８Ｏ５４陶瓷（ｘ＝０．６，ｙ＝０．２，０．３）微波性能的影响，试验结果表明，在其他工艺因素控制得当时，预烧温度和烧结温度对微波性能的影响最大。在预烧温度１０５０℃，烧结温度１２００℃下，其微波特性参数εｒ＝７６．１９，Ｑ·ｆ＝１０．２ＴＨｚ，（ｆ＝４．５ＧＨｚ）。本系统陶瓷的烧结温度比一般文献低１００℃左右，性能仍不错。进一步研究可为制备低温烧结微波陶瓷提供可能。     

阳极铝箔交流腐蚀发孔对比容的影响

采用５０Ｈｚ交流电腐蚀发孔和进一步腐蚀阳极铝箔，在腐蚀箔表面形成透明钝化型腐蚀膜且蚀孔孔径较大。在交流电腐蚀过程中不产生发黑、掉粉和减薄现象。另外，该工艺对盐酸浓度和硫酸添加剂浓度的适应范围很宽。     

不锈钢基底高电流密度YBCO超导线材

室温下应用Ａｒ＋ 离子源辅助准分子脉冲激光沉积（００２）取向的ＹＳＺ（Ｙｔｔｒｉａ－ｓｔａｂｉｌｉｚｅｄ ｚｉｒｃｏ－ｎｉａ）过渡层薄膜于不锈钢基底上;基底加温至７５０℃,用准分子脉冲激光沉积高电流密度ＹＢＣＯ（ＹＢａ２Ｃｕ３Ｏ７－ ｘ） 高温超导线材。实验结果表明：ＹＢＣＯ 超导线材临界温度Ｔｃ ≥９０ Ｋ （Ｒ＝０）,临界电流密度Ｊｃ ≥１×１０６ Ａ／ｃｍ ２（７７ Ｋ,０ Ｔ）。     

SiC异质结双极晶体管的高频性能

用一种简练的异质结双极晶体管（ＨＢＴ）模型来模拟ＳｉＣ基双极晶体管的高频和大功率特性。研究了一种外壳温度在２７℃（３００Ｋ）到６００℃（８７３Ｋ）下的６Ｈ－ＳｉＣ／３Ｃ－ＳｉＣＨＢＴ。将其高频大功率特性与ＡｌＧａＡｓ／ＧａＡｓＨＢＴ作了比较。不出所料，欧姆接触电阻限制了ＳｉＣＨＢＴ的高频性能。现在看来，在ＳｉＣ上只能可靠地产生１×１０￣（－４）Ω－ｃｍ￣２的接触电阻。所以ｆ＿Ｔ和ｆ＿（ｍａｘ）的最高实际值仅分别为４．４ＧＨｚ和３．２ＧＨｚ。但假定发射极、基极和集电极的接触电阻低到１×１０￣（－６）Ω时，则６Ｈ／３ＣＳｉＣＨＢＴ的ｆ＿Ｔ和ｆ＿（ｍａｘ）分别可达到３１．１ＧＨｚ和１２．７６Ｈｚ。     

低压铝箔交流腐蚀研究

在３０Ｈｚ频率下，通过铝箔在ＨＣｌ＋Ｈ２ＳＯ４＋ＨＮＯ３＋Ｈ３ＰＯ４体系中的交流腐蚀，研究腐蚀液组成中腐蚀主体及缓蚀剂对铝箔腐蚀的作用，探讨腐蚀过程中电源频率、腐蚀液温度、电流密度及腐蚀时间对铝箔腐蚀的影响。腐蚀液组成的配比恰当，有利于比容的提高。在特定的频率下采用合适的腐蚀液温度、适宜的电流密度和腐蚀时间可以提高铝箔的静电容量。     

GaAs／AlGaAs多量子阱二维面阵红外探测器

本文报道１０×１６元二维面阵ＧａＡｓ／ＡｌＧａＡｓ多量子阱红外探测器的研究进展．通过表面光栅耦合，采用垂直入射的工作模式，在Ｔ＝８０Ｋ时探测率为２．９e１０ｃｍ·Ｈｚ（１／２）／Ｗ，电压响应率为１．３e４Ｖ／Ｗ．各测试单元间探测率和电压响应率的偏差小于１８％，串音小于０．４５％，在最大探测率偏置条件下，器件的暗电流密度为６．２e－）Ａ／ｃｍ２．     

广义e—bent函数

本文针对广义ｅ－ｂｅｎｔ函数进行了讨论，证明了此类函数仅包括ｂｅｎｔ函数，常数函数和形如ｆ（ｘ１，ｘ２，…，ｘｎ）＝α０＋（ｘ１＋α１）（ｘ２＋α２）…的函数，其中αｉ∈｛０，１｝，ｉ＝０，１，…，ｎ。     

共沉淀法制备Ba(Mg_(1/3)Ta_(2/3))O_3陶瓷的研究

对用化学共沉淀法制备Ｂａ （Ｍｇ１／３Ｔａ２／３） Ｏ３ （ＢＭＴ） 陶瓷及其烧结特性进行了研究。结果表明其烧结温度比用传统方法降低了１８０～２５０℃。在１ ４００℃时获得了致密的陶瓷,其体积密度达理论密度的９６％ ,晶粒排列紧密,介电特性：Ｑ×ｆ＝ ６５ ０００ ＧＨｚ,εｒ＝ ２３～２５,在ｆ＝ １０ＧＨｚ,ｔ＝ － ２０～＋ ６０℃时τｆ ＝ （０～３）×１０－ ６℃－ １。     

电容器铝箔交流腐蚀扩面机理研究

实现铝电解电容器小型化的关键是铝电极箔电解腐蚀扩面过程的人为设计。为实现这一目标,本文就目前尚不清楚的交流腐蚀扩面机制进行了系统分析研究。首先研究了高纯铝箔在水溶液中的热力学和在盐酸溶液中的动力学行为,接着详细地研究了铝在交流电的负半周所发生的变化,以及这些变化对交流正半周铝的点蚀的萌生和生长的影响,并从理论上推导出控制交流负半周腐蚀膜形成的数学关系式。在此基础上,提出了铝在交流负半周发生的四种变化,以及交流腐蚀扩面机理。根据这一机理,提出了铝箔的交流腐蚀工艺优化原则,并用实验对这一原则进行了初步验证。本论文的主要内容如下：     

Faster image template matching in the sum of the absolute value ofdifferences measure

Given an mxm image I and a smaller nxn image P, the computation of an (m-n+1)x(m-n+1) matrix C where C(i, j) is of the form C(i,j)=Sigma(k=0)(n-1)Sigma(k'=0) (n-1)f(I(i+k,j+k'), P(k,k')), 0=/相似文献   

表观电化学参数对铝箔交流电侵蚀的影响

改变交流电密度 (J)、电解液温度 (T)及盐酸浓度 (ci)侵蚀电容器铝箔 ,并以表观电化学参数(J/ ci T)为依据 ,通过侵蚀铝箔的表面形貌和侵蚀箔比容的变化规律 ,研究了铝箔在纯盐酸中受〔Cl- 〕和〔H+ 〕影响的交流侵蚀机制。     

Effects of differential etching and masking resist preparation on the quality of the reactive-ion-etched aluminum and aluminum alloys

The conventional method used for aluminum (Al) and aluminum alloy (Al + Si, Al + Si + Cu) delineation in integrated circuits is mainly by wet chemical etching. Because of its isotropic characteristic, wet chemical etching becomes inadequate for patterning Al metal lines with linewidths narrower than about 4 Μm. In this work, Al and Al alloys (Al + 2% Si; Al + 1% Si + 1% Cu) were reactively etched in SiCl₄ plasma using patterned photoresist as the etch-mask. Resist patterns were generated either by conventional processing methods or by tri-level resist techniques which included hard-baking (200°C, ≤ 30 min), and two consecutive reactive ion etchings in CF₄ and 0₂ plasmas. Masking resists prepared by the tri-level resist technique retained their integrity during exposure to a SiCl₄ plasma, and significantly improved resolution and fidelity of pattern transfer from resist to underlying Al or Al alloy film. The substrate surface of the reactively etched Al + Si + Cu sample was considerably rougher than that of the Al or Al + Si sample due to the high concentration of Cu accumulated at the metal/substrate region during RIE process.     

硫酸/盐酸比例和Al~(3+)含量对铝箔隧道孔生长的影响

研究了硫酸/盐酸比例、温度和Al3+含量对高纯铝箔隧道孔生长的影响,发现随着硫酸浓度增加,温度对隧道孔极限长度和孔径的影响减小,在本文条件下隧道孔生长的临界温度最低可降低到35℃。在电解液中一定含量的Al3+可以避免铝箔表面形成大孔,从而改善隧道孔分布均匀性。     

Novel Design Approach for X-Band GaAs Monolithic Analog 1/4 Frequency Divider

A novel analog frequency divider which can generate a 1/4 frequency component is proposed. The frequency divider consists of a dual-gate FET and a two-stage capacitor-resistor coupled amplifier. This circuit configuration also enables achieving a small-size GaAs MMIC analog frequency divider. In this analog frequency divider, the input signal f/sub 0/ is mixed with signal component f/sub 0//x caused by noise or transients in a feedback loop. Then, a (1 -- 1/x)f/sub 0/ IF component is induced and is again mixed with the input signal. This process delivers the f/sub 0//x component regeneratively. Resultant continuous signal components f/sub 0//x and (1-1/x)f/sub 0/ have a harmonic relation when the system reaches a steady state. The f/sub 0//x component can be mainly obtained at an output port of the frequency divider. The operation band was simulated using a SPICE II computer program. The designed bandwidth and conversion gain for the 1/4 frequency divider are 8.5-10.6 GHz and -3 dB, respectively. Based on the simulation, a GaAs monolithic analog 1/4 frequency divider was made and tested. The developed 1/4 frequency divider provides a 8.5-10.2-GHz operation bandwidth and --5+-1-dB conversion gain. The designed and experimental values are in good agreement. The frequency division band can be shifted to higher frequency (10.65-11.2 GHz) by adopting the external matching circuit at the GaAs chip output port. The proposed analog frequency divider circuit can be applied not only for 1/4 frequency division, but also for 1/n frequency division (interger n > 2).     

Precise Design of a Bandpass Filter Using High-Q Dielectric Ring Resonators

A precise design is presented for a bandpass filter constructed by placing TE/sub 01delta/ dielectric ring resonators coaxially in a TE/sub 01/ cutoff circular waveguide. On the basis of a rigorous analysis by the mode- matching technique, the interresonator coupling coefficients are determined accurately from the calculation of two resonant frequencies f/sub sh/ and f/sub op/ when the structurally symmetric plane is short- and open-circuited. For the TE/sub 01delta/ ring resonator,the resonant frequency f/sub 0/, the temperature coefficient tau/sub f/, the unloaded Q(Q/sub u/), and the other resonances are also calculated accurately in a similar way. From the calculations, the optimum dimensions are determined to obtain the maximum Q/sub u/, as F/sub r/ = f/sub r/ /f/sub 0/ is kept constant, where f/sub r/ is the next higher resonant frequency the ring resonator using low-loss ceramics (epsilon/sub r/ = 24.3, tan delta = 5 x 10/sup -5/) has Q/sub u/ = 16800 at 12 GHz and tau/sub f/ = 0.1+-0.5 ppm/° C, while the rod one has Q/sub u/ = 14700. A four-stage Chebyshev filter having ripple of 0.04 dB and equiripple bandwidth of 27.3 MHz at f/sub 0/ =11.958 GHz is fabricated using these resonator; the measured frequency responses agree well with theory. The insertion loss is 0.9 dB, which corresponds to Q/sub u/ = 9800.     

AlGaN/GaN MIS-HFETs with f/sub T/ of 163 GHz using cat-CVD SiN gate-insulating and passivation Layers

Al/sub 0.4/Ga/sub 0.6/N/GaN heterostructure field-effect transistors (HFETs) with an AlGaN barrier thickness of 8 nm and a gate length (L/sub G/) of 0.06-0.2 /spl mu/m were fabricated on a sapphire substrate. We employed two novel techniques, which were thin, high-Al-composition AlGaN barrier layers and SiN gate-insulating, passivation layers formed by catalytic chemical vapor deposition, to enhance high-frequency device characteristics by suppressing the short channel effect. The HFETs with L/sub G/=0.06-0.2 /spl mu/m had a maximum drain current density of 1.17-1.24 A/mm at a gate bias of +1.0 V and a peak extrinsic transconductance of 305-417 mS/mm. The current-gain cutoff frequency (f/sub T/) was 163 GHz, which is the highest value to have been reported for GaN HFETs. The maximum oscillation frequency (f/sub max/) was also high, and its value derived from the maximum stable gain or unilateral gain was 192 or 163 GHz, respectively.     

影响高压阳极铝箔隧道孔极限长度的因素

研究了高压阳极铝箔在HCl-H2SO4腐蚀体系中,H2SO4/HCl浓度比、Al3+浓度、温度和电流密度对隧道孔长度和铝箔芯层厚度的影响规律。结果表明:提高H2SO4/HCl浓度比、Al3+浓度温度和电流密度,均可缩短隧道孔长度和增加芯层厚度。提出隧道孔的生长受Al3+在隧道孔中的扩散和铝箔表面扩散层中的扩散共同控制,可以对上述因素的影响规律做出更合理的解释。     

Li2O-B2O3复合掺杂对BaAl2Si2O8陶瓷结构与介电性能的影响

采用传统固相反应工艺,按质量分数合成BaO-Al2O3-SiO2-5%(xLi2O-yB2O3)(x=0. 2~0. 6,y=0. 8~0. 4)陶瓷。研究xL-yB烧结助剂对BAS系微波介质陶瓷的结构和介电性能的影响。通过Clausius-Mossotti公式计算讨论了BAS理论与实验介电常数的差异。研究结果表明:xL-yB烧结助剂中Li+进入钡长石Ba2+位,并产生了O2-空位,促进BAS六方相向单斜相转变。添加适当比例的xL-yB烧结助剂后,BAS陶瓷的烧结温度从1400℃降低到925℃,同时BAS陶瓷样品密度、品质因数(Q×f)值以及谐振频率温度系数(τf)得到改善。当烧结助剂为0. 5L-0. 5B,烧结温度为925℃时,可获得综合性能相对较好的BAS陶瓷,其介电性能:εr=6. 74,Q×f=26670 GHz,τf=-21. 09×10-6℃-1。