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Influence of Triangle Structure Defect on the Carrier Lifetime of the 4H-SiC Ultra-Thick Epilayer 下载免费PDF全文
Effect of triangle structure defects in a 180-μm-thick as-grown n-type 4H-SiC homoepitaxial layer on the carrier lifetime is quantitatively analyzed, which is grown by a horizontal hot-wall chemical vapor deposition reactor.By microwave photoconductivity decay lifetime measurements and photoluminescence measurements, the results show that the average carrier lifetime of as-grown epilayer across the whole wafer is 2.59μs, while it is no more than 1.34μs near a triangle defect(TD). The scanning transmission electron microscope results show that the triangle structure defects have originated from 3C-SiC polytype and various types of as-grown stacking faults.Compared with the as-grown stacking faults, the 3C-SiC polytype has a great impact on the lifetime. The reduction of TD is essential to increasing the carrier lifetime of the as-grown thick epilayer. 相似文献
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4H-SiC Schottky barrier diodes with semi-insulating polycrystalline silicon field plate termination 下载免费PDF全文
Based on the theoretical analysis of the 4H-SiC Schottky-barrier diodes(SBDs) with field plate termination, 4H-SiC SBD with semi-insulating polycrystalline silicon(SIPOS) FP termination has been fabricated. The relative dielectric constant of the SIPOS dielectric first used in 4H-SiC devices is 10.4, which is much higher than that of the SiO2dielectric,leading to benefitting the performance of devices. The breakdown voltage of the fabricated SBD could reach 1200 V at leakage current 20 μA, about 70% of the theoretical breakdown voltage. Meanwhile, both of the simulation and experimental results show that the length of the SIPOS FP termination is an important factor for structure design. 相似文献
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本文通过对4H-SiC同质外延化学反应和生长条件的分析,建立了4H-SiC同质外延生长的Grove模型,并结合实验结果进行了分析和验证.通过理论分析和实验验证,得到了外延中氢气载气流量和生长温度对4H-SiC同质外延生长速率的影响.研究表明:外延生长速率在衬底直径上为碗型分布,中心的生长速率略低于边缘的生长速率;随着载气流量的增大,生长速率由输运控制转变为反应速率控制,生长速率先增大而后逐渐降低;载气流量的增加,会使高温区会发生漂移,生长速率的理论值和实验出现一定的偏移;随着外延生长温度的升高,化学反应速率和气相转移系数都会增大,提高了外延速率;温度对外延反应速率的影响远大于对生长质量输运的影响,当温度过分升高后,外延生长会进入质量控制区;但过高的生长温度导致源气体在生长区边缘发生反应,生成固体粒子,使实际参与外延生长的粒子数减少,降低了生长速率,且固体粒子会有一定的概率落在外延层上,严重影响外延层的质量.通过调节氢气流量,衬底旋转速度和生长温度,可以有效的控制外延的生长速度和厚度的均匀性. 相似文献
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针对目前太赫兹光谱仪的数据采集和数据处理软件不能兼容的情况,设计了一个基于LabVIEW软件平台的THz时域光谱分析软件。主要研究了THz时域光谱系统的反射式以及透射式样品光学信息提取算法、支持向量机分类算法、以及偏最小二乘等分析算法以及它们的LabVIEW实现。该软件采用全LabVIEW代码实现,能够实现样品光学信息提取,物质分类识别以及多组分样品浓度分析,并且具有很高的移植性,可扩展性,与数据采集软件具有很好的兼容性。利用该光谱分析软件,分析了三种塑化剂的THz时域光谱信号,得到了它们在THz波段的折射率和吸收系数, 结果表明三种塑化剂可以用THz时域光谱完全区分,软件运行稳定可靠。 相似文献
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基于Lyapunov方法提出实现开放量子系统中目标态为无消相干子空间中纯态时收敛的控制策略.在假定被控系统哈密顿量各个本征态的能级差互不相同并且任意能级都是直接耦合的前提下,给出了一个关于观测算符的充分条件使系统最大不变集只包含目标态.选择观测算符平均值为Lyapunov函数,在相互作用绘景下设计控制律,并利用Barbalat引理分析系统的最大不变集.证明了如果满足所提条件,无消相干子空间中系统的任意本征态或叠加态的目标态都是全局渐近稳定的;被控系统能够从任意初始态转移到期望的目标态.同时给出了一种利用Schmidt正交化来构造观测算符的方法,并且在一个三能级系统的仿真实验上验证了所提方法的正确性. 相似文献
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Passivation effects of phosphorus on 4H-SiC(0001) Si dangling bonds: A first-principles study 下载免费PDF全文
The effect of phosphorus passivation on 4H-SiC(0001) silicon(Si) dangling bonds is investigated using ab initio atomistic thermodynamic calculations. Phosphorus passivation commences with chemisorption of phosphorus atoms at high-symmetry coordinated sites. To determine the most stable structure during the passivation process of phosphorus, a surface phase diagram of phosphorus adsorption on SiC(0001) surface is constructed over a coverage range of 1/9–1 monolayer(ML). The calculated results indicate that the 1/3 ML configuration is most energetically favorable in a reasonable environment. At this coverage, the total electron density of states demonstrates that phosphorus may effectively reduce the interface state density near the conduction band by removing 4H-SiC(0001) Si dangling bonds. It provides an atomic level insight into how phosphorus is able to reduce the near interface traps. 相似文献
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