为了优化传统AlGaN/GaN high electron mobility transistors结构表面电场分布,提高器件击穿电压和可靠性,本文利用不影响AlGaN/GaN异质结极化效应的Si3N4钝化层电荷分布,提出了一种Si3N4钝化层部分固定正电荷AlGaN/GaN high electron m...为了优化传统AlGaN/GaN high electron mobility transistors结构表面电场分布,提高器件击穿电压和可靠性,本文利用不影响AlGaN/GaN异质结极化效应的Si3N4钝化层电荷分布,提出了一种Si3N4钝化层部分固定正电荷AlGaN/GaN high electron mobility transistors新结构.Si3N4钝化层中部分固定正电荷通过电场调制效应使表面电场分布中产生新的电场峰而趋于均匀.新电场峰使得新结构栅边缘和漏端高电场有效降低,器件击穿电压从传统结构的296V提高到新结构的650V,而且可靠性改善.通过Si3N4与AlGaN界面横、纵向电场分布,说明了产生表面电场峰的电场调制效应,为设计Si3N4层部分固定正电荷新结构提供了科学依据.Si3N4钝化层部分固定正电荷的补偿作用,使沟道二维电子气浓度增加,导通电阻减小,输出电流提高.展开更多
240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge ef...240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge effects.Here,it is revealed that the peak optical output power increases by 81.83%with the size shrinking from 50.0 to 25.0μm.Thereinto,the LEE increases by 26.21%and the LEE enhancement mainly comes from the sidewall light extraction.Most notably,transversemagnetic(TM)mode light intensifies faster as the size shrinks due to the tilted mesa side-wall and Al reflector design.However,when it turns to 12.5μm sized micro-LEDs,the output power is lower than 25.0μm sized ones.The underlying mechanism is that even though protected by SiO2 passivation,the edge effect which leads to current leakage and Shockley-Read-Hall(SRH)recombination deteriorates rapidly with the size further shrinking.Moreover,the ratio of the p-contact area to mesa area is much lower,which deteriorates the p-type current spreading at the mesa edge.These findings show a role of thumb for the design of high efficiency micro-LEDs with wavelength below 250 nm,which will pave the way for wide applications of deep ultraviolet(DUV)micro-LEDs.展开更多
氮化镓器件凭借优异的性能在抗辐照应用领域备受关注,为探究不同结构的氮化镓器件抗质子辐照能力,开展了对增强型Cascode级联结构和P-GaN栅结构GaN高电子迁移率晶体管(High Electron Mobility Transistor,HEMT)器件的5MeV质子辐照试验,...氮化镓器件凭借优异的性能在抗辐照应用领域备受关注,为探究不同结构的氮化镓器件抗质子辐照能力,开展了对增强型Cascode级联结构和P-GaN栅结构GaN高电子迁移率晶体管(High Electron Mobility Transistor,HEMT)器件的5MeV质子辐照试验,分析器件电学特性退化规律,并明确其质子辐照效应损伤机制。试验发现,质子辐照注量越大,Cascode结构器件阈值电压负漂越严重,同时饱和漏极电流增加越显著,当质子注量大于1×10^(13) p∙cm^(-2)时,器件电学特性退化程度开始降低。对于P-GaN栅结构GaN HEMT而言,辐照后电学特性退化规律与Cascode结构器件截然相反,且退化程度明显小于Cascode结构器件,表明增强型Cascode结构器件对质子辐照更加敏感。结合低频噪声测试,发现随辐照注量的增加,Cascode结构器件噪声功率谱密度先增加后保持稳定,其变化规律与电学特性退化情况相吻合。分析认为,5 MeV质子辐照诱导发生电离损伤使Cascode结构器件内部级联的Si基金属-氧化物-半导体场效应晶体管(Metal-Oxide-Semiconductor Field Effect Transistor,MOSFET)栅氧化层产生了更多的氧化物陷阱电荷与界面态陷阱电荷,是Cascode结构器件对质子辐照敏感的主要原因。研究结果对GaN功率器件加固设计和航天应用器件选型具有一定的参考价值。展开更多
文摘为了优化传统AlGaN/GaN high electron mobility transistors结构表面电场分布,提高器件击穿电压和可靠性,本文利用不影响AlGaN/GaN异质结极化效应的Si3N4钝化层电荷分布,提出了一种Si3N4钝化层部分固定正电荷AlGaN/GaN high electron mobility transistors新结构.Si3N4钝化层中部分固定正电荷通过电场调制效应使表面电场分布中产生新的电场峰而趋于均匀.新电场峰使得新结构栅边缘和漏端高电场有效降低,器件击穿电压从传统结构的296V提高到新结构的650V,而且可靠性改善.通过Si3N4与AlGaN界面横、纵向电场分布,说明了产生表面电场峰的电场调制效应,为设计Si3N4层部分固定正电荷新结构提供了科学依据.Si3N4钝化层部分固定正电荷的补偿作用,使沟道二维电子气浓度增加,导通电阻减小,输出电流提高.
基金This work was supported by National Key R&D Program of China(2022YFB3605103)the National Natural Science Foundation of China(62204241,U22A2084,62121005,and 61827813)+3 种基金the Natural Science Foundation of Jilin Province(20230101345JC,20230101360JC,and 20230101107JC)the Youth Innovation Promotion Association of CAS(2023223)the Young Elite Scientist Sponsorship Program By CAST(YESS20200182)the CAS Talents Program(E30122E4M0).
文摘240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge effects.Here,it is revealed that the peak optical output power increases by 81.83%with the size shrinking from 50.0 to 25.0μm.Thereinto,the LEE increases by 26.21%and the LEE enhancement mainly comes from the sidewall light extraction.Most notably,transversemagnetic(TM)mode light intensifies faster as the size shrinks due to the tilted mesa side-wall and Al reflector design.However,when it turns to 12.5μm sized micro-LEDs,the output power is lower than 25.0μm sized ones.The underlying mechanism is that even though protected by SiO2 passivation,the edge effect which leads to current leakage and Shockley-Read-Hall(SRH)recombination deteriorates rapidly with the size further shrinking.Moreover,the ratio of the p-contact area to mesa area is much lower,which deteriorates the p-type current spreading at the mesa edge.These findings show a role of thumb for the design of high efficiency micro-LEDs with wavelength below 250 nm,which will pave the way for wide applications of deep ultraviolet(DUV)micro-LEDs.
文摘氮化镓器件凭借优异的性能在抗辐照应用领域备受关注,为探究不同结构的氮化镓器件抗质子辐照能力,开展了对增强型Cascode级联结构和P-GaN栅结构GaN高电子迁移率晶体管(High Electron Mobility Transistor,HEMT)器件的5MeV质子辐照试验,分析器件电学特性退化规律,并明确其质子辐照效应损伤机制。试验发现,质子辐照注量越大,Cascode结构器件阈值电压负漂越严重,同时饱和漏极电流增加越显著,当质子注量大于1×10^(13) p∙cm^(-2)时,器件电学特性退化程度开始降低。对于P-GaN栅结构GaN HEMT而言,辐照后电学特性退化规律与Cascode结构器件截然相反,且退化程度明显小于Cascode结构器件,表明增强型Cascode结构器件对质子辐照更加敏感。结合低频噪声测试,发现随辐照注量的增加,Cascode结构器件噪声功率谱密度先增加后保持稳定,其变化规律与电学特性退化情况相吻合。分析认为,5 MeV质子辐照诱导发生电离损伤使Cascode结构器件内部级联的Si基金属-氧化物-半导体场效应晶体管(Metal-Oxide-Semiconductor Field Effect Transistor,MOSFET)栅氧化层产生了更多的氧化物陷阱电荷与界面态陷阱电荷,是Cascode结构器件对质子辐照敏感的主要原因。研究结果对GaN功率器件加固设计和航天应用器件选型具有一定的参考价值。
