Al_(x)Ga_(1–x)N插入层对双沟道n-Al_(0.3)Ga_(0.7)N/GaN/i-Al_(x)Ga_(1–x)N/GaN HEMT器件性能的影响  

Effect of inserted Al_(x)Ga_(1–x)N layer on characteristic of doublechannel n-Al_(0.3)Ga_(0.7)N/GaN/i-Al_(x)Ga_(1–x)N/GaN HEMT

作　　者：蔡静 姚若河[1] 耿魁伟[1,2] Cai Jing;Yao Ruo-He;Geng Kui-Wei(School of Microelectronics,South China University of Technology,Guangzhou 510640,China;Sino-Singapore International Joint Research Institute,Guangzhou 510700,China)

机构地区：[1]华南理工大学微电子学院,广州510640 [2]中新国际联合研究院,广州510700

出　　处：《物理学报》2022年第16期325-334,共10页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2018YFB1802100);广东省重点领域研发计划(批准号:2019B010143003)资助的课题。

摘　　要：双沟道AlGaN/GaNHEMT器件在电子限域性、电流运输等方面优于单沟道结构,且能更好地缓解电流崩塌,提高设备的运行能力,在高功率应用中具有重要意义.本文对n-Al_(0.3)Ga_(0.7)N/GaN/i-Al_(x)Ga_(1–x)N/GaN结构中的电荷状态以及运输性质进行研究.通过求解一维薛定谔方程和泊松方程,获得其电势、电场和电子分布,分析了双沟道中二维电子气状态与合金无序散射、位错散射的关系.结果表明,在第一沟道中,当Al_(x)Ga_(1–x)N的Al组分和厚度提升时,二维电子气密度逐渐减小,合金无序散射的减弱使迁移率增大,位错散射增强致迁移率变小,总迁移率主要由合金无序散射决定.在第二沟道中,当Al_(x)Ga_(1–x)N的Al组分和厚度提升时,二维电子气密度随之增大,由于较低的势垒高度以及高渗透电子的作用,第二沟道中的合金无序散射影响更大,合金无序散射迁移率随Al_(x)Ga_(1–x)N层的Al组分和厚度的增加而减少且变化趋势逐渐趋于平缓,位错散射作用的减弱导致迁移率的提升.总体上,第一沟道势阱中受到的位错散射低于第二沟道势阱.随着背势垒厚度的增加,第二沟道中主导的散射机制逐渐从位错散射转为合金无序散射.With the demand for high-temperature,high-frequency,and high-power microwave applications increasing,AlGaN/GaN high electron mobility transistors(HEMT) have attracted much attention in recent years.Twodimensional electron gas(2DEG) induced by spontaneous polarization and piezoelectric polarization caused by the uneven charge distribution on Ga-N bond and the large tensile strain guarantees the high performance of AlGaN/GaN HEMT.Compared with single-channel devices,dual-channel AlGaN/GaN HEMT has great application prospects in enhancing the electronic confinement,current drive and alleviating the current collapse.In order to study the physical characteristics,the carrier state and transportation characterization of nAl_(0.3)Ga_(0.7)N/GaN/i-Al_(x)Ga_(1-x)N/GaN multilayer structure are investigated.By calculating the one-dimensional self-consistent Poisson-Schr?dinger,the energy band diagram,electric field and charge distribution in the devices are obtained.The 2 DEG,alloy disorder and dislocation scattering mechanism in the device are also analyzed by analytical models in which the wave function in finite barriers and Fermi’s rule are used.With Al_(x)Ga_(1-x)N layer thickness increasing from 0 nm to 30 nm and Al content rising from 0.1 to 0.2,the concentration of 2 DEG localized in the heterointerface is diminished in the first channel.Simultaneously,mobility limited by alloy disorder scattering increases monotonically with the r composition occupation number and the Al_(x)Ga_(1-x)N thickness proportion increasing.Besides,dislocation scattering on carriers is strengthened in the same quantum well,resulting in the lower mobility.In the second channel,2DEG density gets growing when the variables mentioned above is enlarged.The mobility restricted by alloy disorder scattering shows a reverse trend with the variation of the Al_(x)Ga_(1-x)N thickness and Al fraction,which more greatly affect the carriers in the parasitic channel due to the lower barrier height and high permeable carriers.Furthermore,the effect of disl

关 键 词：双沟道 2 DEG 迁移率 

分 类 号：TN386[电子电信—物理电子学]