NiO/Ga_(2)O_(3) p+-n异质结功率二极管中陷阱介导双极型电荷输运研究  

Trap-mediated bipolar charge transport in NiO/Ga_(2)O_(3)p+-n heterojunction power diodes

作　　者：汪正鹏 巩贺贺 郁鑫鑫 纪晓丽 任芳芳 杨燚 顾书林 郑有炓 张荣 叶建东 Zhengpeng Wang;He-He Gong;Xin-Xin Yu;Xiaoli Ji;Fang-Fang Ren;Yi Yang;Shulin Gu;Youdou Zheng;Rong Zhang;Jiandong Ye(School of Electronic Science and Engineering,Nanjing University,Nanjing 210023,China;Shenzhen Research Institute of Shandong University,Shenzhen 518000,China)

机构地区：[1]School of Electronic Science and Engineering,Nanjing University,Nanjing 210023,China [2]Shenzhen Research Institute of Shandong University,Shenzhen 518000,China

出　　处：《Science China Materials》2023年第3期1157-1164,共8页中国科学（材料科学（英文版）

基　　金：supported by the National Key R&D Program of China(2022YFB3605400);the State Key Research and Development Project of Guangdong(2020B010174002);the National Natural Science Foundation of China(62234007,U21A20503 and U21A2071).

摘　　要：构筑NiO/Ga_(2)O_(3)p+-n异质结是克服Ga_(2)O_(3)p型掺杂瓶颈从而实现双极型功率电子器件的有效途径,然而限制器件性能的缺陷行为与双极型电荷输运等物理机制尚不明晰.本论文研究了NiO/Ga_(2)O_(3)p+-n异质结中陷阱介导的载流子输运、俘获和复合动力学之间的内在关联特性.变温电流-电压特性的量化分析表明,在正偏亚阈值区,陷阱辅助隧穿占据主导地位,符合多数载流子陷阱介导的Shockley-Read-Hall复合模型,其陷阱激活能为0.64 eV,与深能级瞬态谱测试的陷阱能级位置(EC-0.67 eV)非常吻合;当正向偏压大于器件开启电压时,器件输运特性由少数载流子扩散所主导,器件理想因子接近于1.在反向偏置的高场作用下,器件漏电机制则由β-Ga_(2)O_(3)体材料中的陷阱引起的PooleFrenkel(PF)发射所导致.PF发射的势垒高度为0.75 eV,与等温变频深能级瞬态谱测得的陷阱能级位置(EC-0.75 eV)相一致.这一工作有助于建立NiO/Ga_(2)O_(3)p+-n异质结中双极型电荷输运和深能级缺陷行为间的内在关联,对理解和发展Ga_(2)O_(3)双极型功率整流器件具有重要的参考价值.The construction of p-NiO/n-Ga_(2)O_(3)heterojunction becomes a popular alternative to overcome the technological bottleneck of p-type Ga_(2)O_(3)for developing bipolar power devices for practical applications, whereas the identification of performance-limiting traps and the bipolar transport dynamics are still not exploited yet. To this end, the fundamental correlation of carrier transport, trapping and recombination kinetics in NiO/β-Ga_(2)O_(3)p+-n heterojunction power diodes has been investigated. The quantitative modeling of the temperature-dependent current-voltage characteristics indicates that the modified Shockley-Read-Hall recombination mediated by majority carrier trap states with an activation energy of 0.64 eV dominates the trap-assisted tunneling process in the forward subthreshold conduction regime, while the minority carrier diffusion with near-unity ideality factors is overwhelming at the bias over the turn-on voltage. The leakage mechanism at high reverse biases is governed by the Poole-Frenkel emissions through the β-Ga_(2)O_(3)bulk traps with a barrier height of 0.75 eV, which is supported by the identification of majority bulk traps with the energy level of EC-0.75 eV through the isothermal capacitance transient spectroscopic analysis. These findings bridge the knowledge gap between bipolar charge transport and deeplevel trap behaviors in Ga_(2)O_(3), which is crucial to understand the reliability of Ga_(2)O_(3)bipolar power rectifiers.

关 键 词：深能级瞬态谱 双极型 功率电子器件 电荷输运 功率二极管 载流子输运 开启电压 亚阈值区 

分 类 号：TB34[一般工业技术—材料科学与工程] TN31[电子电信—物理电子学]