氧等离子体活化β-Ga_(2)O_(3)/SiO_(2)低温键合工艺  

Low Temperature Bonding ofβ-Ga_(2)O_(3)/SiO_(2) by Oxygen Plasma Activation

作　　者：马旭[1,2] 穆文祥 侯童[1] 董岳 余博文 李阳 贾志泰 MA Xu;MU Wenxiang;HOU Tong;DONG Yue;YU Bowen;LI Yang;JIA Zhitai(Institute of Novel Semiconductors,State Key Laboratory of Crystal Materials,Shandong University,Jinan 250100,China;Shenzhen Research Institute of Shandong University,Shenzhen 518057,Guangdong,China;Shandong Research Institute of Industrial Technology,Jinan 250100,China)

机构地区：[1]山东大学新一代半导体材料研究院,晶体材料国家重点实验室,济南250100 [2]山东大学深圳研究院,广东深圳518057 [3]山东省工业技术研究院,济南250100

出　　处：《硅酸盐学报》2024年第10期3273-3282,共10页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(52002219,51932004);广东省重点研发计划(2020B010174002);深圳市基础研究计划(JCYJ20210324132014038)。

摘　　要：采用O2等离子体活化键合技术,实现了β-Ga_(2)O_(3)与SiO_(2)的低温直接键合。通过对O2等离子体处理时间进行调控,系统研究了接触角、羟基密度随处理时间的变化。随着O2等离子体活化时间的增加,SiO_(2)和β-Ga_(2)O_(3)晶片表面亲水性大幅度增强,晶片表面的羟基密度明显提升。同时探究了退火温度对衬底表面质量及键合强度的影响,发现键合强度随着退火温度的增加而提升,但较高退火温度容易导致β-Ga_(2)O_(3)衬底的开裂。通过扫描电子显微镜和透射电子显微镜对键合界面进行分析,键合界面的O、Ga、Si元素在退火过程中发生充分扩散。测试说明,采用O2等离子体活化方法成功地实现了β-Ga_(2)O_(3)/SiO_(2)晶片的异质集成。由于β-Ga_(2)O_(3)和SiO_(2)衬底可以在不需要真空处理的情况下实现原子级的结合,技术路线成本低,因此本工作提出的直接键合技术将有助于推动β-Ga_(2)O_(3)材料在器件方面的发展及应用。Introductionβ-Ga_(2)O_(3) as a ultra-wide bandgap semiconductor material with a great development potential has a bandgap width of 4.8 eV,and a theoretical breakdown electric field of 8 MV/cm.Its Baliga advantage value ofβ-Ga_(2)O_(3) is also several times greater than that of silicon carbide(SiC)or gallium nitride(GaN).However,the low thermal conductivity ofβ-Ga_(2)O_(3) seriously affected the device's heat dissipation and the application in the high-power field.Wafer bonding is an indispensable key technology in semiconductor devices,which enables the formation of new structures,efficient fabrication,device integration,and cost reduction.The silicon substrate with the advantages of low cost and high thermal conductivity is an important substrate material for heterogeneous integrations.SiO_(2) layer is easily formed on the surface of silicon,and the surface structure of SiO_(2) consists of a Si-O-Si three-dimensional network structure together with an unsaturated Si-O structure,and the existence of this structure is conducive to reducing the probability of bubble generation,thus improving the quality of the bonding bonding interface,so it is easier to realize the bonding of silicon andβ-Ga_(2)O_(3) by using SiO_(2) as an intermediate layer.This paper was to analyze the effect of O_(2) plasma activation on the wafer surface,including changes in contact angle,roughness,and surface chemical composition.In addition,the effect of annealing temperature on the strength and thermal stability of the bond structure and the structure and composition of theβ-Ga_(2)O_(3)/SiO_(2) bond interface was also discussed.Methods SiO_(2)/Si substrate with the thickness of 550μm andβ-Ga_(2)O_(3) single crystals sunstrate with the thickness of 650μm were prepared.The two wafers were cleaned with alcohol and acetone via ultrasonic cleaning,and isopropanol for 10 min,then rinsed with deionized water and blown dry with N2.Also,β-Ga_(2)O_(3) and SiO_(2)/Si substrates were processed by oxygen plasma in a reactive ion etching(RIE)equ

关 键 词：β-氧化镓 二氧化硅 氧气等离子体活化 低温直接键合 异质集成 

分 类 号：TB332[一般工业技术—材料科学与工程]