中子辐照对AlGaN/GaN高电子迁移率晶体管器件电特性的影响  

Effect of neutron irradiation on the electrical properties of AlGaN/GaN high electron mobility transistors

作　　者：谷文萍[1,2] 张林[1] 李清华[1] 邱彦章[1] 郝跃[2] 全思[1] 刘盼枝 

机构地区：[1]长安大学电子与控制工程学院,西安710064 [2]西安电子科技大学微电子学院宽禁带半导体材料与器件教育部重点实验室,西安710071

出　　处：《物理学报》2014年第4期278-283,共6页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:513270407;61354);预先研究项目(批准号:51311050112;51308030102;51308040301);中央高校基本科研业务费(批准号:CHD2012JC095);陕西省自然科学基金(批准号:2013JQ7028)资助的课题~~

摘　　要：本文采用能量为1 MeV的中子对SiN钝化的AlGaN/GaN HEMT(高电子迁移率晶体管)器件进行了最高注量为1015cm-2的辐照.实验发现:当注量小于1014cm-2时,器件特性退化很小,其中栅电流有轻微变化(正向栅电流IF增加,反向栅电流IR减小),随着中子注量上升,IR迅速降低.而当注量达到1015cm-2时,在膝点电压附近,器件跨导有所下降.此外,中子辐照后,器件欧姆接触的方块电阻退化很小,而肖特基特性退化却相对明显.通过分析发现辐照在SiN钝化层中引入的感生缺陷引起了膝点电压附近漏电流和反向栅泄漏电流的减小.以上结果也表明,SiN钝化可以有效地抑制中子辐照感生表面态电荷,从而屏蔽了绝大部分的中子辐照影响.这也证明SiN钝化的AlGaN/GaN HEMT器件很适合在太空等需要抗位移损伤的环境中应用.SiN-passivated AlGaN/GaN high electron mobility transistors （HEMTs） are exposed to 1 MeV neutron at fluences up to 10^15 cm-2. The device shows a negligible degradation at neutron fluences below 10^14 cm-2, while the gate leakage current （Ig） slightly changes （the forward IF increases, the reverse IR decreases.） at low fluencies and the IR degrades dramatically at fiuences higher than 10^14 cm-2. Moreover, near the knee voltage, the transconductance decreases at fluences up to 10^15 cm-2, but the Schottky characteristicis become degraded after neutron irradiation. And the 20-hour annealing results do not show any significant annealing recovery effect at room temperature, while the parameters also continues to degrade a little. Therefore, the drain current （near the knee voltage） and the If degradation of SiN-passivated AlGaN/GaN HEMT can be attributed to the irradiation induced defects in SiN passivation layers, demonstrating that the effectiveness of the SiN layer in passivating surface state in the source-gate spacer and gate- drain spacer is undiminished by neutron irradiation. And the Ohmic contact is so relatively robust to neutron, but the Schottky characteristics degrade obviously. The annealing results prove that the damage induced by neutron may be recovered more difficultly. SiN-passivated AlGaN/GaN HEMT appear to be an attractive candidate for space and terrestrial applications where resistance to displacement damage is required.

关 键 词：ALGAN GAN HEMT 中子辐照 缺陷 退火 

分 类 号：O571.5[理学—粒子物理与原子核物理]