重掺直拉硅对重金属Cr的内吸杂能力

研究了重掺硼(HB)、重掺砷(HAs)以及重掺锑(HSb)直拉(CZ)硅片对重金属Cr的内吸杂能力.将不同程度(～1012cm-2,～1014cm-2)沾污Cr的硅片在N2下进行常规的高-低-高三步退火,并由全反射X射线荧光光谱(TRXF)测量退火前后样品表面Cr的含量.结果表明在三种重掺硅中,HB硅片的内吸杂能力最强,HAs硅片次之,HSb硅片最低.     

硅片直接键合界面的存在对器件性能的影响

利用电子透射显微镜(TEM)和俄歇分析仪(AES)观察硅片直接键合界面结构,在界面存在一个小于2nm厚的非晶区-硅氧化物。此界面具有良好的吸杂效应,在同一退火温度下,退火时间愈长,吸杂现象愈明显。因此键合界面的存在改善了晶体管的性能。     

氮对重掺锑直拉硅中氧沉淀的影响

通过在不同条件下退火,研究氮杂质对重掺锑硅(HSb- Si)中氧沉淀的影响.实验结果表明,在高温单步退火(10 0 0～115 0℃)和低高两步退火(6 5 0℃+10 5 0℃)后,掺氮HSb- Si中与氧沉淀相关的体微缺陷的密度都要远远高于一般的HSb- Si.这说明在HSb- Si中,氮能分别在高温和低温下促进氧沉淀的生成.因此,可以认为与轻掺直拉硅一样,在HSb- Si中,氮氧复合体同样能够生成,因而促进了氧沉淀的形核.实验结果还表明氮的掺入不影响HSb硅中氧沉淀的延迟行为.     

氮对重掺锑直拉硅中氧沉淀的影响

通过在不同条件下退火,研究氮杂质对重掺锑硅(HSb-Si)中氧沉淀的影响.实验结果表明,在高温单步退火(1000～1150℃)和低高两步退火(650℃+1050℃)后,掺氮HSb-Si中与氧沉淀相关的体微缺陷的密度都要远远高于一般的HSb-Si.这说明在HSb-Si中,氮能分别在高温和低温下促进氧沉淀的生成.因此,可以认为与轻掺直拉硅一样,在HSb-Si中,氮氧复合体同样能够生成,因而促进了氧沉淀的形核.实验结果还表明氮的掺入不影响HSb硅中氧沉淀的延迟行为.     

冶金法n型多晶硅磷、硼吸杂实验的研究

研究了冶金法n型多晶硅片磷吸杂、硼吸杂效果及其机理。研究发现,经1 000℃/4h磷吸杂后,硅片平均少子寿命从1.21μs提高到11.98μs;经950℃/1h硼吸杂后,平均少子寿命从1.52μs提升到10.74μs。两种吸杂处理后,硅片电阻率从0.2Ω.cm提高到0.5Ω.cm。结果表明,两种吸杂工艺使得硅片表面形成的重磷、重硼扩散层对金属杂质有较好的吸杂作用,从而减少载流子的复合中心,改善多晶硅片的性能。     

Ramping热退火直拉重掺锑硅衬底片的增强氧沉淀

本文报道了一种改进本征吸杂技术——低温短时热退火工艺,以增强本征吸杂效果．在本征吸杂工艺的低温热退火中,用连续的线性缓慢升温（Ｒａｍｐｉｎｇ）退火替代常规的长时间低温恒温退火,应用于直拉（ＣＺ）重掺Ｎ型硅衬底片,明显增加了氧沉淀等体微缺陷密度,这些高密度氧沉淀物在随后ＩＣ器件热工艺中继续长大,成为稳定的高效本征吸杂中心．从经典的成核沉淀理论,讨论了Ｒａｍｐｉｎｇ热退火重掺硅衬底片增强氧沉淀机理．     

掺Si补偿Cu高阻n-GaAs单晶

用水平布里奇曼法(HB法)研制掺Si补偿Cu的n-GaAs高阻单晶.既要提高多晶背景纯度,减少总杂质含量(包括减少掺Cu量和掺Si量,单晶中Cu的质量分数要≤2.00×10-5,Si的质量分数要≤1.00×10-6),又要采用熔体Cu,Si双掺的方法生长单晶,将单晶切片,并划成圆片,然后分组放入炉内在确定温度下和一定时间内进行退火.研制中发现Cu主要集中在晶体表面,导致同一晶片的上部呈p型高阻,而中下部呈n型低阻,退火可使Cu在晶片中均匀分布.     

磷铝吸杂在多晶硅太阳电池中的应用

研究了多晶硅的浓磷扩散吸杂、铝吸杂、磷-铝联合吸杂(双面蒸铝).采用准稳态光电导衰减法测试了吸杂前后多晶硅片的有效少数载流子寿命,发现磷-铝联合吸杂于硅片少子寿命的提高最大达30μs以上,其次是磷吸杂,铝吸杂再次之.采用吸杂后的多晶硅片制备了1cm×1cm的太阳电池,与相同条件下未经吸杂制备的电池相比,发现三种吸杂方式都能提高电池的各项电学特性,其中磷-铝联合吸杂提高电池效率最大,达40%以上,最差为铝吸杂,只有15%左右的提高,这与吸杂后所测得的少子寿命的变化趋势一致.实验说明三种吸杂方式在不同程度上促成了硅片界面晶格应力对重金属杂质的吸附作用,减少了载流子的复合中心,从而提高了有效少数载流子的寿命;而有效少数载流子的寿命直接影响到电池的效率.     

硅片背面激光损伤的吸杂效果

本文介绍了硅片背面激光损伤吸杂实验,用金相显微镜观察证实了高温退火后激光损伤的热稳定性,研究了激光损伤对氧化层错(OSF)和载流子寿命的影响,用中子活化分析法测出了吸杂效果。     

GaN紫外探测器的Ti/Al接触的电学特性

在非故意掺杂的和掺Si的GaN薄膜上蒸镀Ti(24nm)/Al(nm)薄膜,氮气环境下400～800℃范围内进行退火。实验结果表明,在非故意掺杂的样品上,随退火温度的升高,肖特基势垒高度下降,理想因子升高,表面状况逐渐变差,600℃退火形成较低接触电阻的欧姆接触,比接触电阻率为3.03×10-4Ωcm2,而载流子浓度为5.88×1018cm-3的掺Si的样品未退火就形成欧姆接触,比接触电阻可达到4.03×10-4Ωcm2。     

求解流水车间调度问题的混合粒子群算法

本文提出了一种混合的元启发式方法HDCPSO用于求解置换流水车间调度问题中的最小化完成时间.该算法将粒子群算法和迭代贪心算法(Iterative Greedy,IG)相结合,利用IG算法中的作业毁坏(Destruction)和构造(Construction)操作来对粒子进行变异,降低群体发生早熟的可能.引入了个体徘徊概...     

Excess leakage-current noise in junction field-effect transistors

Measurements are reported of the excess gate leakage current IG in several n channel f.e.t.s, showing that IG varies exponentially with the inverse square root of the bias voltage between drain and gate. IG shows full shot noise, together with a component of the form Ign2?IG?/f? where values of 1.4 and 1.6 have been found for ? and ?, respectively.     

Recurrent Functional-Link-Based Fuzzy-Neural-Network-Controlled Induction-Generator System Using Improved Particle Swarm Optimization

A recurrent functional-link (FL)-based fuzzy-neural-network (FNN) controller with improved particle swarm optimization (IPSO) is proposed in this paper to control a three-phase induction-generator (IG) system for stand-alone power application. First, an indirect field-oriented mechanism is implemented for the control of the IG. Then, an AC/DC power converter and a DC/AC power inverter are developed to convert the electric power generated by a three-phase IG from variable frequency and variable voltage to constant frequency and constant voltage, respectively. Moreover, two online-trained recurrent FL-based FNNs are introduced as the regulating controllers for both the DC-link voltage of the AC/DC power converter and the AC line voltage of the DC/AC power inverter. Furthermore, IPSO is adopted to adjust the learning rates to improve the online learning capability of the recurrent FL-based FNNs. Finally, some experimental results are provided to demonstrate the effectiveness of the proposed recurrent FL-based FNN-controlled IG system.     

Confidence limits for steady state availability of systems with lognormal operating time and inverse Gaussian repair time

A 100 p% confidence interval for the steady state availability of a system is derived, when the operating time distribution is lognormal and the repair time distribution is Inverse Gaussian (IG). It is assumed that one of the parameters of lognormal distribution and also the ratio of parameters of IG distribution are known.     

Comparison of intrinsic gettering and epitaxial wafers in terms of soft error endurance and other characteristics of 64k bit dynamic RAM

Intrinsic gettering (IG) and P/P⁺epitaxial wafers are compared in terms of soft error endurance and other characteristics of a 64k bit dynamic RAM. It was confirmed that soft error rate is improved in IG wafers, while it is deteriorated in P/P⁺epitaxial wafers. However, when epitaxial layer thickness is reduced to a certain value, the soft error rate tends to be improved. Several other characteristics of 64k bit DRAM's were also evaluated for devices made on IG and epitaxial wafers with various denuded zone (DZ) widths and epitaxial layer thicknesses, respectively.     

Cr含量对CuCr触头材料性能的影响

研究了ＣｕＣｒ触头材料中Ｃｒ含量对其性能的影响，结果表明，当Ｃｒ含量相对较低时，ＣｕＣｒ触头具有较大的分断能力。     

NTDCZSi内吸除技术的研究

利用中子嬗变掺杂(NTD)技术制备的CZSi(NTDCZSi)片在高温退火时,由于辐照缺陷与直拉硅中杂质氧的相互作用,可以加速内吸除(IG)效应的实现,获得理想的表面清洁区和体内吸杂区.本文探讨了将NTD技术与IG技术相结合的问题,并讨论了NTDCZSi IG效应机理.     

A new closed-form of ASEP and channel capacity with MRC and selection combining over Inverse Gaussian shadowing

This paper analyse and investigate the performance of communication system with maximal ratio combining (MRC) and selection combining (SC) over Inverse Gaussian (IG) fading distribution. All formats of coherent and non-coherent modulation schemes are considered and novel analytical expressions of average symbol error probability (ASEP) with diversity are derived. Gamma and IG fading distributions are popularly used as a mathematically less complex solution to lognormal in the open literature. Hence, we provide a comparative analysis between IG and gamma fading with the aim to provide a quantitative measure of the difference between the two distributions in the context of ASEP. Moreover, the novel closed-form expressions of channel capacity under transmission schemes such as optimal rate adaptation (ORA) and channel inversion fixed rate (CIFR) are derived and analysed with MRC and SC diversity over IG fading. The analytical results have been validated with the Monte Carlo simulations and the exact numerical results.     

氧本征吸除低温退火工艺的研究和改进

讨论了硅片中氧沉淀形成的机理，推荐一种本征吸除的改进技术，用以增强吸除效果。在本征吸除工艺的低温退火中，用连续的线性升温退火代替常规的恒温退火。采用改进的本征吸除工艺后，可增加硅片表面ＭＯＳ结构少子产生寿命和降低Ｐ＋Ｎ结二极管的反向电流。     

The Impacts of Cation Stoichiometry and Substrate Surface Quality on Nucleation,Structure, Defect Formation,and Intermixing in Complex Oxide Heteroepitaxy–LaCrO3 on SrTiO3(001)

The ability to design and fabricate electronic devices with reproducible properties using complex oxides is critically dependent on our ability to controllably synthesize these materials in thin‐film form. Structure‐property relationships are intimately tied to film and interface composition. Here the effect of cation stoichiometry on structural quality and defect formation in LaCrO₃ heteroepitaxial films prepared using molecular beam epitaxy is reported. From first principles the regions of stability of various candidate defects, along with the predicted effects of these defects on structural parameters, are calculated as a function of Cr and O chemical potential. Epitaxial LaCrO₃ films readily nucleate and remain coherently strained on SrTiO₃(001) over a wide range of La‐to‐Cr atom ratios, but La‐rich films are of considerably lower structural quality than stoichiometric and Cr‐rich films. Cation imbalances are accompanied by anti‐site defect formation. Cation mixing occurs at the interface for all La‐to‐Cr ratios investigated and is not quenched by deposition on SrTiO₃(001) at ambient temperature. Indiffused La atoms occupy Sr sites. Intermixing is effectively quenched by using molecular beam epitaxy to deposit LaCrO₃ at ambient temperature on defect free Si(001). However, analogous pulsed laser deposition on Si is accompanied by cation mixing.