Design and Fabrication of Thermo-Optic 4×4 Switching Matrix in Silicon-on-Insulator

A rearrangeable nonblocking thermo-optic 4×4 switching matrix,which consists of five 2×2 multimode interference-based Mach-Zehnder interferometer(MMI-MZI) switch elements,is designed and fabricated.The minimum and maximum excess loss for the matrix are 6.6 and 10.4dB,respectively.The crosstalk in the matrix is measured to be between -12 and -19.8dB.The switching speed of the matrix is less than 30μs.The power consumption for the single switch element is about 330mW.

Fabrication and Evaluation of Bragg Gratings on Optimally Designed Silicon-on-Insulator Rib Waveguides Using Electron-Beam Lithography

The fabrication of Bragg gratings on silicon-on-insulator （SOI） rib waveguides using electron-beam lithography is presented. The grating waveguide is optimally designed for actual photonic integration. Experimental and theoretical evaluations of the Bragg grating are demonstrated. By thinning the SOl device layer and deeply etching the Bragg grating, a large grating coupling coefficient of 30cm^-1 is obtained.

棉花SOD基因家族生物信息学分析

研究基于镉胁迫下棉花幼苗根系的转录组测序数据,鉴定获得16个棉花SOD基因,并对其进行生物信息学分析。结果表明:16个棉花SOD基因编码的蛋白长度为127~333 aa,相对分子质量为13048.69~35974.31 Da,等电点为4.43~8.50,均为非分泌蛋白,且都无跨膜结构特征,表现为亲水性;其中75%属于酸性蛋白,69%属于稳定蛋白;大部分亚细胞定位在叶绿体;16个棉花SOD可分为Fe-SOD、Mn-SOD和Cu/Zn-SOD 3个亚家族,3个亚家族均含有各自的保守基序,其中Fe-SOD和Mn-SOD亚家族亲缘关系较近,推测两者功能更相似。棉花SOD家族基因的鉴定、分析对棉花SOD基因功能及镉响应机制研究具有借鉴意义,可为筛选耐镉棉花品种提供基因资源。

藜麦SOD家族基因的鉴定及其对混合盐碱胁迫的响应

超氧化物歧化酶(superoxide dismutase,SOD)是植物抗氧化系统的关键酶,在保护植物免受生物和非生物胁迫方面发挥重要作用。以拟南芥SOD为基础,通过序列比对在藜麦基因组中鉴定出12个SOD基因,分别定位于细胞核、微体及线粒体,在11条染色体上不均匀分布,其编码蛋白质三级结构显示Cu/Zn-SODs与Fe-SODs为同源二聚体,Mn-SODs为同源四聚体。CqSOD基因内含子/外显子分布模式不尽相同,内含子数介于4~7个,保守基序差异明显。系统发育关系显示,SOD蛋白可分为Cu/Zn-SODs、Fe-SODs及Mn-SODs 3个亚族。此外,所有的CqFe-SODs及CqMn-SODs启动子区都含有脱落酸激素反应顺式元件,CqSOD12与11个CqSOD蛋白及4个CqCAT蛋白存在相互作用。表达谱分析表明,12个CqSOD基因对混合盐碱及硝普钠均有较强响应。研究结果为SOD基因在植物发育和胁迫响应中的作用及分子机制研究奠定基础。

scAAV9-IGF-1对SOD1-G93A小鼠抗凋亡通路的作用

目的 探索以自我互补双链腺相关病毒9为载体介导的人胰岛素样生长因子-1 (scAAV9-IGF-1)对SOD1-G93A转基因小鼠抗凋亡通路的作用。方法 采用肌萎缩侧索硬化(ALS)的动物模型即转基因SOD1-G93A突变型及野生型(wild type-SOD1,WT-SOD1)小鼠,在其出生后60 d龄时,雌性同窝阳性SOD1-G93A转基因小鼠采用随机的方法分配到治疗组及溶剂对照组,治疗组全身多点肌肉注射scAAV9-IGF-1,溶剂对照组多点肌肉注射AAV9-GFP,同年龄WT-SOD1作为阴性对照组。在肌肉注射40~50 d后,利用PCR技术检测腰髓中IGF-1含量的变化,同时检测抗凋亡通路因子Bcl-xl、Bcl-2的mRNA含量变化,通过免疫组化染色观察抗凋亡通路因子Bcl-xl、Bcl-2在小鼠腰髓前角神经元中的表达。结果 PCR技术检测显示scAAV9-IGF-1处理后,腰髓中IGF-1的mRNA含量显著高于GFP对照组,抗凋亡通路因子Bclxl、Bcl-2的mRNA含量均高于溶剂对照组(均P<0.05),而与WT组差异无统计学意义。免疫组化染色结果显示,治疗组中抗凋亡通路蛋白Bcl-xl,Bcl-2在小鼠腰髓前角神经元中的表达多于溶剂对照组,并且与WT阴性对照组相当。结论 scAAV9-IGF-1可以激活SOD1-G93A转基因小鼠模型中的抗凋亡通路,其通过上调Bcl-xl,Bcl-2的mRNA水平,进而增加Bcl-xl、Bcl-2的蛋白表达,从而产生抗凋亡的作用。

Study on the defect-related emissions in the light self-ion-implanted Si films by a silicon-on-insulator structure

This paper reports that the Si＋ self-ion-implantation are conducted on the silicon-on-insulator wafers with the 2SSi＋ doses of 7 ×1012, 1 × 1013, 4 × 1013, and 3× 1014 cm-2, respectively. After the suitable annealing, these samples are characterized by using the photoluminescence technique at different recorded temperatures. Plentiful emission peaks are observed in these implanted silicon-on-insulator samples, including the unwonted intense P~ band which exhibits a great potential in the optoelectronic application. These results indicate that severe transformation of the interstitial clusters can be manipulated by the implanting dose at suitable annealing temperatures. The high critical temperatures for the photoluminescence intensity growth of the two signatures are well discussed based on the thermal ionization model of free exciton.

Analysis of single-event transient sensitivity in fully depleted silicon-on-insulator MOSFETs

Based on 3 D-TCAD simulations, single-event transient(SET) effects and charge collection mechanisms in fully depleted silicon-on-insulator(FDSOI) transistors are investigated. This work presents a comparison between28-nm technology and 0.2-lm technology to analyze the impact of strike location on SET sensitivity in FDSOI devices. Simulation results show that the most SET-sensitive region in FDSOI transistors is the drain region near the gate. An in-depth analysis shows that the bipolar amplification effect in FDSOI devices is dependent on the strike locations. In addition, when the drain contact is moved toward the drain direction, the most sensitive region drifts toward the drain and collects more charge. This provides theoretical guidance for SET hardening.

Mechanism of floating body effect mitigation via cutting off source injection in a fully-depleted silicon-on-insulator technology

In this paper, the effect of floating body effect （FBE） on a single event transient generation mechanism in fully depleted （FD） silicon-on-insulator （SOI） technology is investigated using three-dimensional technology computer-aided design （3D- TCAD） numerical simulation. The results indicate that the main SET generation mechanism is not carder drift/diffusion but floating body effect （FBE） whether for positive or negative channel metal oxide semiconductor （PMOS or NMOS）. Two stacking layout designs mitigating FBE are investigated as well, and the results indicate that the in-line stacking （IS） layout can mitigate FBE completely and is area penalty saving compared with the conventional stacking layout.

New Method of Total Ionizing Dose Compact Modeling in Partially Depleted Silicon-on-Insulator MOSFETs

On the basis of a detailed discussion of the development of total ionizing dose （TID） effect model, a new commercial-model-independent TID modeling approach for partially depleted silicon-on-insulator metal-oxide- semiconductor field effect transistors is developed. An exponential approximation is proposed to simplify the trap charge calculation. Irradiation experiments with 60Co gamma rays for IO and core devices are performed to validate the simulation results. An excellent agreement of measurement with the simulation results is observed.

Total dose radiation response of modified commercial silicon-on-insulator materials with nitrogen implanted buried oxide

Nitrogen ions of various doses are implanted into the buried oxide （BOX） of commercial silicon-on-insulator （SOI） materials, and subsequent annealings are carried out at various temperatures. The total dose radiation responses of the nitrogen-implanted SOI wafers are characterized by the high frequency capacitance-voltage （C-V） technique after irradi- ation using a Co-60 source. It is found that there exist relatively complex relationships between the radiation hardness of the nitrogen implanted BOX and the nitrogen implantation dose at different irradiation doses. The experimental results also suggest that a lower dose nitrogen implantation and a higher post-implantation annealing temperature are suitable for improving the radiation hardness of SOI wafer. Based on the measured C V data, secondary ion mass spectrometry （SIMS）, and Fourier transform infrared （FTIR） spectroscopy, the total dose responses of the nitrogen-implanted SOI wafers are discussed.

Improvement of total-dose irradiation hardness of silicon-on-insulator materials by modifying the buried oxide layer with ion implantation

The hardening of the buried oxide （BOX） layer of separation by implanted oxygen （SIMOX） silicon-on-insulator （SOI） wafers against total-dose irradiation was investigated by implanting ions into the BOX layers. The tolerance to total-dose irradiation of the BOX layers was characterized by the comparison of the transfer characteristics of SOI NMOS transistors before and after irradiation to a total dose of 2.7 Mrad（SiO2）. The experimental results show that the implantation of silicon ions into the BOX layer can improve the tolerance of the BOX layers to total-dose irradiation. The investigation of the mechanism of the improvement suggests that the deep electron traps introduced by silicon implantation play an important role in the remarkable improvement in radiation hardness of SIMOX SOI wafers.

Influence of nitrogen implantation into the buried oxide on the radiation hardness of silicon-on-insulator wafers

In order to improve the total-dose radiation hardness of the buried oxide of separation by implanted oxygen silicon- on-insulator wafers, nitrogen ions were implanted into the buried oxide with a dose of 1016 cm-2, and subsequent annealing was performed at 1100 ℃. The effect of annealing time on the radiation hardness of the nitrogen implanted wafers has been studied by the high frequency capacitance-voltage technique. The results suggest that the improvement of the radiation hardness of the wafers can be achieved through a shorter time annealing after nitrogen implantation. The nitrogen-implanted sample with the shortest annealing time 0.5 h shows the highest tolerance to total-dose radiation. In particular, for the 1.0 and 1.5 h annealing samples, both total dose responses were unusual. After 300-krad（Si） irradiation, both the shifts of capacitance-voltage curve reached a maximum, respectively, and then decreased with increasing total dose. In addition, the wafers were analysed by the Fourier transform infrared spectroscopy technique, and some useful results have been obtained.

An analytical model for coplanar waveguide on silicon-on-insulator substrate with conformal mapping technique

In this paper, the authors present an analytical model for coplanar waveguide on silicon-on-insulator substrate. The four-element topological network and the conformal mapping technique are used to analyse the capacitance and the conductance of the sandwich substrate. The validity of the model is verified by the full-wave method and the experimental data. It is found that the inductance, the resistance, the capacitance and the conductance from the analytical model show they are in good agreement with the corresponding values extracted from experimental Sparameter until 10 GHz.

Early effect modeling of silicon-on-insulator SiGe heterojunction bipolar transistors

Silicon germanium （SiGe） heterojunction bipolar transistor （HBT） on thin silicon-on-insulator （SOI） has recently been demonstrated and integrated into the latest SOI BiCMOS technology. The Early effect of the SOI SiGe HBT is analysed considering vertical and horizontal collector depletion, which is different from that of a bulk counterpart. A new compact formula of the Early voltage is presented and validated by an ISE TCAD simulation. The Early voltage shows a kink with the increase of the reverse base-collector bias. Large differences are observed between SOI devices and their bulk counterparts. The presented Early effect model can be employed for a fast evaluation of the Early voltage and is useful to the design, the simulation and the fabrication of high performance SOI SiCe devices and circuits.

Design and Fabrication of MEMS Gyroscopes on the Silicon-on-insulator Substrate with Decoupled Oscillation Modes

The mode coupling is a major factor to affect the precision of the micro electromechanical systems（MEMS） gyroscope. Currently, many MEMS gyroscopes with separate oscillation modes for drive and detection have been developed to decrease the mode coupling, but the gyroscope accuracy can not satisfy the high-precision demand well. Therefore, high performance decoupled MEMS gyroscopes is still a hot topic at present. An innovative design scheme for a MEMS gyroscope is designed, and in this design, the inertial mass is divided into three parts including the inner mass, the outer mass and the main frame mass. The masses are supported and separated by a set of mutually orthogonal beams to decouple their movements. Moreover, the design is modelled by multi-port-element network（MuPEN） method and the simulation results show that the mode coupling of the gyroscope between driving and sensing mode was eliminated effectively. Furthermore, we proposed a new silicon-on-insulator（SOI） process to fabricate the gyroscope. The scale factor of the fabricated gyroscope is 8.9 mV/（（~）os） and the quality factor（Q-factor） is as high as 600 at atmosphere pressure, and then, the resonant frequency, scale factor and bias drift has been test. Process and test results show that the proposed MEMS gyroscope are effective for decrease mode coupling, furthermore, it can achieve a high performance at atmosphere pressure. Furthermore, the MEMS gyroscope can achieve a high performance at atmosphere pressure. The research can be taken as good advice for the design and fabrication of MEMS gyroscope, meanwhile, it also provides technical support for speeding up of MEMS gyroscope industrialization.

Analysis and Simulation of S-shaped Waveguide in Silicon-on-insulator

The simulation and analysis of S-shaped waveguide bend are presented.Bend radius larger than 30 mm assures less than 0.5 dB radiation loss for a 4-μm-wide silicon-on-insulator waveguide bend with 2-μm etch depth.Intersection angle greater than 20° provides negligible crosstalk (<-30 dB) and very low insertion loss.Any reduction in bend radius and intersection angle is at the cost of the degradation of characteristics of bent waveguide and intersecting waveguide, respectively.

Substrate bias effects on collector resistance in SiGe heterojunction bipolar transistors on thin film silicon-on-insulator

An analytical expression for the co/lector resistance of a novel vertical SiGe heterojunction bipolar transistor （HBT） on thin film silicon-on-insulator （SOI） is obtained with the substrate bias effects being considered. The resistance is found to decrease slowly and then quickly and to have kinks with the increase of the substrate-collector bias, which is quite different from that of a conventional bulk HBT. The model is consistent with the simulation result and the reported data and is useful to the frequency characteristic design of 0.13 μtm millimeter-wave SiGe SOI BiCMOS devices.

Modeling of a triple reduced surface field silicon-on-insulator lateral double-diffused metal–oxide–semiconductor field-effect transistor with low on-state resistance

An analytical model for a novel triple reduced surface field（RESURF） silicon-on-insulator（SOI） lateral doublediffused metal–oxide–semiconductor（LDMOS） field effect transistor with n-type top（N-top） layer, which can obtain a low on-state resistance, is proposed in this paper. The analytical model for surface potential and electric field distributions of the novel triple RESURF SOI LDMOS is presented by solving the two-dimensional（2D） Poisson＇s equation, which can also be applied to single, double and conventional triple RESURF SOI structures. The breakdown voltage（BV） is formulized to quantify the breakdown characteristic. Besides, the optimal integrated charge of N-top layer（Q_（ntop）） is derived, which can give guidance for doping the N-top layer. All the analytical results are well verified by numerical simulation results,showing the validity of the presented model. Hence, the proposed model can be a good tool for the device designers to provide accurate first-order design schemes and physical insights into the high voltage triple RESURF SOI device with N-top layer.

Total Ionizing Dose Response of Different Length Devices in 0.13μm Partially Depleted Silicon-on-Insulator Technology

An anomalous total dose effect that the long length device is more susceptible to total ionizing dose than the short one is observed with the 0.13？μm partially depleted silicon-on-insulator technology. The measured results and 3D technology computer aided design simulations demonstrate that the devices with different channel lengths may exhibit an enhanced reverse short channel effect after radiation. It is ascribed to that the halo or pocket implants introduced in processes results in non-uniform channel doping profiles along the device length and trapped charges in the shallow trench isolation regions.

刺梨SOD基因家族鉴定与表达模式分析

【目的】超氧化物歧化酶(SOD)是植物体内氧自由基的天然清除剂,对于保护植物免受环境胁迫起着关键作用,了解其在刺梨响应干旱胁迫中的作用,为深入研究刺梨SOD基因家族的功能提供基础。【方法】通过生物信息学对刺梨SOD基因家族进行系统鉴定和分析,对其理化性质、染色体位置、基因结构、亚家族进化、顺式作用元件和WGCNA进行全面分析,并利用RT-qPCR分析刺梨SOD基因家族在干旱胁迫下的表达模式。【结果】刺梨SOD基因家族有9个成员,包括4个Cu/ZnSOD基因、3个MnSOD基因和2个FeSOD基因,分布在5条染色体上。基因结构显示,同一亚家族成员的基序组成较为相似,但内含子/外显子排列和数量差异较大。亚家族进化分析发现,MnSOD亚家族较原始,其在所有蛋白质位置都表现出高度保守性,其次是FeSOD和Cu/ZnSOD,Cu/ZnSOD亚家族各序列之间差异较大,又可以分为3个亚类。顺式作用元件分析显示,该家族基因参与多种植物激素、生长发育以及胁迫响应,特别是RrCSD2启动子区含有类黄酮生物合成元件(MBSI)。进一步通过转录组和WGCNA分析发现,RrCSD2所在模块的基因显著富集到黄酮和黄酮醇生物合成、类黄酮生物合成和花生四烯酸代谢等途径,表明RrCSD2可能参与类黄酮代谢过程。RT-qPCR结果显示,在干旱胁迫下,除RrMSD1和RrMSD2的表达水平显著下降外,其余7个基因的表达水平总体呈现上升趋势,特别是RrCSD2和RrCSD3的表达水平显著上调。【结论】刺梨SOD基因在干旱胁迫中起到重要作用。