针对商用SiC绝缘栅双极型晶体管(SiC IGBT)可靠性研究不足的现状,通过高温栅偏(HTGB)试验方法对器件施加正负栅偏及高温应力,研究了其退化机制及耐压能力变化。静态参数变化趋势显示,器件呈现阈值电压不稳定性,且负栅压对特性的影响较...针对商用SiC绝缘栅双极型晶体管(SiC IGBT)可靠性研究不足的现状,通过高温栅偏(HTGB)试验方法对器件施加正负栅偏及高温应力,研究了其退化机制及耐压能力变化。静态参数变化趋势显示,器件呈现阈值电压不稳定性,且负栅压对特性的影响较正栅压更为显著。进一步研究发现,负栅偏试验组中,经120 h HTGB试验后,空穴陷阱捕获能力趋于饱和,阈值电压V_(GE(TH))降至一定程度后趋于稳定,不再显著变化;正栅偏试验组中,阈值电压在特定时间段内出现微弱下降,推测为电子填充近界面氧化物陷阱、暴露更多正电荷所致。HTGB加速试验后,栅极氧化层退化导致器件耐压能力削弱。失效分析结果表明,退化器件的沟道区上方栅极氧化层较JFET区更易发生击穿,与沟道区和单晶硅外延区作为主要工作区域的特性相关。正栅偏时,电子堆积于SiC/SiO_(2)界面;负栅偏时,则引发空穴堆积现象。展开更多
为了解决多层片式陶瓷电容器(MLCC)在高可靠产品应用、研发验证和产品改进等环节对快速可靠性评价技术的需求,提出了一种基于Procopowicz-Vaskas模型(P-V模型)的高加速寿命试验(HALT)评价方法,开展了某10μF 6.3 V MLCC产品在9组不同高...为了解决多层片式陶瓷电容器(MLCC)在高可靠产品应用、研发验证和产品改进等环节对快速可靠性评价技术的需求,提出了一种基于Procopowicz-Vaskas模型(P-V模型)的高加速寿命试验(HALT)评价方法,开展了某10μF 6.3 V MLCC产品在9组不同高温、高电压下的HALT研究。获得了样品在不同温度和电压应力下的失效分布特征,其P-V寿命模型参数的激活能为1.30 eV、电场加速因子为3.79。建立了高容量MLCC产品的HALT寿命模型,为其可靠性快速评价提供了参考。展开更多
本团队通过基于密度泛函理论的第一性原理方法,系统地研究了HfSe2/PtSe2范德瓦尔斯异质结(van der Waals heterostructures,vdWHs)的电子性质,包括堆垛方式、层间耦合、应变和外电场的影响.发现堆垛方式可以调节能带对齐类型--AA,AB′...本团队通过基于密度泛函理论的第一性原理方法,系统地研究了HfSe2/PtSe2范德瓦尔斯异质结(van der Waals heterostructures,vdWHs)的电子性质,包括堆垛方式、层间耦合、应变和外电场的影响.发现堆垛方式可以调节能带对齐类型--AA,AB′和AC′堆垛时为Ⅱ型,AB,AC,AA′则为Ⅰ型.在六种堆垛方式中,AA堆垛是最稳定的,其层间距为2.87A,带隙为1.0 eV,Ⅱ型的能带对齐方式有利于电子-空穴载流子的分离.进一步的计算表明,HfSe_(2)/PtSe_(2)异质结的电子性质可以通过垂直应变和双轴面内应变有效调节:在施加应变或改变层间距后,可以在HfSe_(2)/PtSe_(2)异质结中观察到从Ⅱ型到Ⅰ型能带对齐类型的转变;不仅如此,压缩应变和层间耦合还可以有效调控异质结的带隙大小.本研究将为未来HfSe_(2)/PtSe_(2)异质结在纳米电子及光电设备中的应用提供理论基础.展开更多
Research in biology and medicine is a rapidly expanding field incorporating some of the most fundamental questions concerning structure, function, and purpose. The forefront of new research demands access to advanced ...Research in biology and medicine is a rapidly expanding field incorporating some of the most fundamental questions concerning structure, function, and purpose. The forefront of new research demands access to advanced techniques and instrumentation capable of probing these unanswered questions. Over the past several decades, nano-scale materials and devices ranging from quasione dimensional quantum dots to two dimensional graphene sheets have been engineered and have found applications in nano-bio imaging and spectroscopy. In this review, the incorporation of nanomaterials into three influential spectroscopic and microscopic techniques including fluorescence microscopy, surface plasmon resonance, and sum frequency generation will be introduced. Fluorescence imaging has visualized nanomaterials as compliments or replacements to comparable organic fluorphores, act as a quencher for FRET-based sensing, and serve as a nanoscaffold for molecular beacons. Their versatility in coating materials makes nanomaterials an excellent targeting molecule for any cellular macromolecule or structure. In addition to the targeting capabilities of nanomaterials in fluorescence imaging, surface plasmon resonance has incorporated nanomaterials for applications in signal enhancement, selectivity of target molecules, and the development of more refined and accurate detection. Functionalized nano-particles enhance the capabilities of sum frequency generation vibrational spectroscopy by providing unique surface chemistry which alters target molecule interactions and orientations. In summary, the incorporation of nanomaterials has greatly enhanced the field of biology and medicine and has allowed for the continual advancement of not only research but instrument development.展开更多
文摘针对商用SiC绝缘栅双极型晶体管(SiC IGBT)可靠性研究不足的现状,通过高温栅偏(HTGB)试验方法对器件施加正负栅偏及高温应力,研究了其退化机制及耐压能力变化。静态参数变化趋势显示,器件呈现阈值电压不稳定性,且负栅压对特性的影响较正栅压更为显著。进一步研究发现,负栅偏试验组中,经120 h HTGB试验后,空穴陷阱捕获能力趋于饱和,阈值电压V_(GE(TH))降至一定程度后趋于稳定,不再显著变化;正栅偏试验组中,阈值电压在特定时间段内出现微弱下降,推测为电子填充近界面氧化物陷阱、暴露更多正电荷所致。HTGB加速试验后,栅极氧化层退化导致器件耐压能力削弱。失效分析结果表明,退化器件的沟道区上方栅极氧化层较JFET区更易发生击穿,与沟道区和单晶硅外延区作为主要工作区域的特性相关。正栅偏时,电子堆积于SiC/SiO_(2)界面;负栅偏时,则引发空穴堆积现象。
文摘为了解决多层片式陶瓷电容器(MLCC)在高可靠产品应用、研发验证和产品改进等环节对快速可靠性评价技术的需求,提出了一种基于Procopowicz-Vaskas模型(P-V模型)的高加速寿命试验(HALT)评价方法,开展了某10μF 6.3 V MLCC产品在9组不同高温、高电压下的HALT研究。获得了样品在不同温度和电压应力下的失效分布特征,其P-V寿命模型参数的激活能为1.30 eV、电场加速因子为3.79。建立了高容量MLCC产品的HALT寿命模型,为其可靠性快速评价提供了参考。
文摘本团队通过基于密度泛函理论的第一性原理方法,系统地研究了HfSe2/PtSe2范德瓦尔斯异质结(van der Waals heterostructures,vdWHs)的电子性质,包括堆垛方式、层间耦合、应变和外电场的影响.发现堆垛方式可以调节能带对齐类型--AA,AB′和AC′堆垛时为Ⅱ型,AB,AC,AA′则为Ⅰ型.在六种堆垛方式中,AA堆垛是最稳定的,其层间距为2.87A,带隙为1.0 eV,Ⅱ型的能带对齐方式有利于电子-空穴载流子的分离.进一步的计算表明,HfSe_(2)/PtSe_(2)异质结的电子性质可以通过垂直应变和双轴面内应变有效调节:在施加应变或改变层间距后,可以在HfSe_(2)/PtSe_(2)异质结中观察到从Ⅱ型到Ⅰ型能带对齐类型的转变;不仅如此,压缩应变和层间耦合还可以有效调控异质结的带隙大小.本研究将为未来HfSe_(2)/PtSe_(2)异质结在纳米电子及光电设备中的应用提供理论基础.
文摘Research in biology and medicine is a rapidly expanding field incorporating some of the most fundamental questions concerning structure, function, and purpose. The forefront of new research demands access to advanced techniques and instrumentation capable of probing these unanswered questions. Over the past several decades, nano-scale materials and devices ranging from quasione dimensional quantum dots to two dimensional graphene sheets have been engineered and have found applications in nano-bio imaging and spectroscopy. In this review, the incorporation of nanomaterials into three influential spectroscopic and microscopic techniques including fluorescence microscopy, surface plasmon resonance, and sum frequency generation will be introduced. Fluorescence imaging has visualized nanomaterials as compliments or replacements to comparable organic fluorphores, act as a quencher for FRET-based sensing, and serve as a nanoscaffold for molecular beacons. Their versatility in coating materials makes nanomaterials an excellent targeting molecule for any cellular macromolecule or structure. In addition to the targeting capabilities of nanomaterials in fluorescence imaging, surface plasmon resonance has incorporated nanomaterials for applications in signal enhancement, selectivity of target molecules, and the development of more refined and accurate detection. Functionalized nano-particles enhance the capabilities of sum frequency generation vibrational spectroscopy by providing unique surface chemistry which alters target molecule interactions and orientations. In summary, the incorporation of nanomaterials has greatly enhanced the field of biology and medicine and has allowed for the continual advancement of not only research but instrument development.
