功率MOSFET器件SEGR敏感区域的模拟研究

单粒子栅极穿通（SEGR）是功率MOSFET器件在空间应用时非常重要的失效模式。功率MOSFET的元胞区被普遍认为是对SEGR最敏感的区域。然而试验结果表明SEGR可能会发生在栅极的走线区域,而不是元胞区域。本文通过仿真软件对功率MOSFET内部的三种结构进行模拟评估,发现如果满足某些条件,元胞区域以外的区域可能成为SEGR的敏感区域。最后,对于不同区域本为给出了抑制SEGR的建议。     

采用接口结构的掺钕单模光纤激光器

稀士元素掺杂单模光纤激光器是一种新颖的有源光纤器件.因其可与常规单模光纤、无源光纤器件(如耦合器、偏振器、滤波器和调制器等)等直接连接,使光源与光纤系统间的耦合损耗减至最小,又可实现全光纤网络.另外,它还可以满足某些光纤传感器在光源性能方面的特殊要求.因此,近年来国内外对这一有源光纤器件的研究工作方兴未艾.本文报道掺钕单模光纤的基础性研究.实验 实验中采用国产掺钕单膜光纤,钦的掺杂浓度为4OOppm,芯径为5.0μm,光纤长度     

基于模型迁移学习的木材导热系数预测

木材导热系数对木结构建筑能耗精准预测具有重要意义,然而目前文献中的模型难以提供全面而准确的预测工具,且一些机器学习模型所考虑的因素和样本数有限。本文构建1941年至今含多种特征的导热系数数据库,并开发对比神经网络和迁移学习模型的预测精度。结果表明,结合迁移学习后,导热系数预测精度可提升23%以上,且迁移学习性能在0～0.3 W·m-1·K-1上精度提升明显,更适合于木结构等传热应用中。本文通过创新的模型参数微调迁移策略能为小样本、含大量缺失值的数据集和简单网络结构的导热系数预测提供思路。     

飞秒激光诱导TiO2金红石相变的激光显微拉曼光谱研究

利用激光显微拉曼光谱仪研究了近红外飞秒激光脉冲诱导TiO2金红石晶体所引起的相变.实验发现当激光的脉冲功率为1.0μJ/脉冲时,随着飞秒激光辐照脉冲数的增加,金红石相的Eg模式强度增强,而A1g模式强度减弱,飞秒激光的非线性效应在晶体内部诱导产生了色心;当激光辐照脉冲数为2.5×106时,锐钛矿石相出现;随着激光辐照脉冲数的增加,锐钛矿相的拉曼振动模式强度增强,金红石相的拉曼振动模式强度减弱.     

低压条形栅功率场效应晶体管的研制

介绍一种新型低压平面结构的功率场效应晶体管--条形栅VDMOS. 通过与传统的元胞型结构比较，发现条形栅具有导通电阻小、开关速度快以及工作稳定性高等特点. 还对条形栅VDMOS的工艺做了介绍，其工艺过程简单，实用性强.     

功率MOS器件在不同温度条件下雪崩特性研究

本文使用实验和二维器件模拟仿真方法研究了高压功率MOS器件在不同温度条件下的耐雪崩能力。实验研究了国产功率MOS器件在最大额定工作温度范围(-55℃～150℃)发生的雪崩能量烧毁行为。采用包含电热非等温模型的ISE TCAD二维仿真软件模拟分析器件发生雪崩失效的机理。无嵌位电感实验数据及模拟结果证明,由于器件内部寄生效应及热效应影响,功率MOS器件雪崩耐量可靠性随着温度升高而退化,其主要原因与雪崩过程引起器件内部寄生双极管开启相关。     

Superjunction nanoscale partially narrow mesa IGBT towards superior performance

We present a detailed study of a superjunction(SJ) nanoscale partially narrow mesa(PNM) insulated gate bipolar transistor(IGBT) structure. This structure is created by combining the nanoscale PNM structure and the SJ structure together. It demonstrates an ultra-low saturation voltage(V_(ce(sat))) and low turn-off loss(E_(off)) while maintaining other device parameters. Compared with the conventional 1.2 k V trench IGBT, our simulation result shows that the V_(ce(sat))of this structure decreases to 0.94 V, which is close to the theoretical limit of 1.2 k V IGBT. Meanwhile, the fall time decreases from109.7 ns to 12 ns and the E off is down to only 37% of that of the conventional structure. The superior tradeoff characteristic between V_(ce(sat))and E_(off) is presented owing to the nanometer level mesa width and SJ structure. Moreover, the short circuit degeneration phenomenon in the very narrow mesa structure due to the collector-induced barriers lowering(CIBL) effect is not observed in this structure. Thus, enough short circuit ability can be achieved by using wide, floating P-well technique.Based on these structure advantages, the SJ-PNM-IGBT with nanoscale mesa width indicates a potentially superior overall performance towards the IGBT parameter limit.     

功率MOS和IGBT器件在无嵌位电感开关条件下的动态雪崩特性研究

The ability of high-voltage power MOSFETs and IGBTs to withstand avalanche events under unclamped inductive switching(UIS) conditions is measured.This measurement is to investigate and compare the dynamic avalanche failure behavior of the power MOSFETs and the IGBT,which occur at different current conditions.The UIS measurement results at different current conditions show that the main failure reason of the power MOSFETs is related to the parasitic bipolar transistor,which leads to the deterioration of the avalanche reliability of power MOSFETs.However,the results of the IGBT show two different failure behaviors.At high current mode,the failure behavior is similar to the power MOSFETs situation.But at low current mode,the main failure mechanism is related to the parasitic thyristor activity during the occurrence of the avalanche process and which is in good agreement with the experiment result.     

超荧光光纤光源的工作特性

研制了一种激光二极管泵浦的掺钕超荧光光纤光源,在波长１．０８μｍ处获得了１．０ｍＷ的光功率输出,谱线宽度为２１．２ｎｍ,实验中使用的是掺钕单模光纤,芯径５μｍ,截止波长１．０μｍ,其损耗在泵浦波长０．８μｍ处为１５００ｄＢ／ｋｍ,而在输出波长１．０８μｍ处为１０ｄＢ／ｋｍ。