具有Cr阻挡层的GaAs欧姆接触工艺研究  

GaAs Ohmic Contact Process with Cr Barrier Layer

作　　者：李博 李辉 李晓雪 闫昊 郝永芹 Li Bo;Li Hui;Li Xiaoxue;Yan Hao;Hao Yongqin(State Key Laboratory of High Power Semiconductor Laser,Changchun University of Science and Technology,Changchun 130022,Jilin,China)

机构地区：[1]长春理工大学高功率半导体激光国家重点实验室,吉林长春130022

出　　处：《中国激光》2022年第11期37-46,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(11474038);吉林省科技发展计划项目(20200401073GX)。

摘　　要：研究了金属Cr作为扩散阻挡层的GaAs欧姆接触技术,设计了Au/Cr/AuGe/Ni和Ti/Cr/Au两种欧姆接触合金系统,并对Cr阻挡层厚度与退火条件进行了优化。研究结果表明:两种合金系统均可在380~480℃退火条件下形成欧姆接触,且Au/Cr/AuGe/Ni系统在420℃/60s退火条件下的比接触电阻率为2.63×10^(-6)Ω·cm^(2),相较于在相同基底上镀制的Au/Ni/AuGe/Ni合金系统比接触电阻率的最低值1.54×10^(-5)Ω·cm^(2)降低了近一个数量级,且具有更好的表面形貌;Ti/Cr/Au系统在440℃/60s退火条件下的比接触电阻率为6.99×10^(-7)Ω·cm^(2),且在420~460℃相对较宽的温度范围内均可获得低的比接触电阻率。Objective With the increased use of semiconductor devices,there are high requirements for device performance,which is directly affected by ohmic contact.Low specific contact resistivity is crucial for reducing the contact resistance of a device,thus decreasing the threshold current and improving the electro-optical conversion efficiency.The most widely used alloy system for n-GaAs ohmic contacts is Au/AuGe/Ni,which has the advantages of a mature process and high ohmic contact quality.However,the low melting point of AuGe eutectic causes varying degrees of shrinkage of Au and Ge during the alloying process,which deteriorates the surface of the metal layer.The p-GaAs ohmic contact,Ti/Pt/Au alloy system,has high reliability and stability in an ohmic contact preparation but is expensive for large-scale preparations.In the ohmic contact alloy system,the diffusion barrier layer acts as an isolation layer to prevent mutual diffusion between the electrode layers,thus significantly improving the stability and reliability of the ohmic contact.Therefore,new ohmic contact structures have been proposed to improve ohmic contact characteristics.Cr has good stability,high conductivity,and resistance to wear and corrosion,which can enhance the wear resistance and film quality of the alloy.In this study,GaAs-based p/n ohmic contact alloy system,Au/Cr/AuGe/Ni,and Ti/Cr/Au alloy systems were designed using Cr as the diffusion barrier layer.The alloying conditions and thickness of the Cr layer were optimized,and their advantages in ohmic contact characteristics were analyzed and compared with conventional alloy systems.Methods The n-type GaAs(1×10^(18) cm^(-3))and p-type GaAs(1×10^(19) cm^(-3))samples were grown using metalorganic chemical vapor deposition(MOCVD).Further,Au/Cr/AuGe/Ni(300nm/40-55nm/100nm/5nm)and Ti/Cr/Au(40nm/20-50nm/200nm)were deposited on the surface of the two sample types using magnetron sputtering technology.The 10 electrode rings of the dot transmission line model were fabricated using photolithography and li

关 键 词：材料 半导体器件 欧姆接触 扩散阻挡层 合金化 比接触电阻率 

分 类 号：TN305.93[电子电信—物理电子学]