热处理温度对金锗薄膜电阻的影响
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摘要
金锗薄膜是作为电子器件欧姆电极的重要材料,真空热处理是降低欧姆电极接触电阻的重要方法.本文研究了基于PVD方法生长的Au_9Ge_1薄膜的表面形貌及其电阻与真空热处理温度之间的关系.研究发现,当真空热处理温度达到180°C时,薄膜表面开始出现由于锗原子的析出形成的零星小点.随着真空热处理温度的上升,锗原子的析出从分散的点逐渐转变成发散的雪花状,薄膜的电阻也随之出现明显下降.当真空热处理温度达到265°C时,薄膜电阻率达到最小值～2.0175Ω/mm.当真空热处理温度继续升高时,表层金原子开始团聚形成小岛状结核,同时薄膜电阻开始急剧增大.当真空热处理温度达到280°C时,薄膜电阻率达到～6.4×10~5Ω/mm,此时薄膜断电.相比于未经任何热处理的样品, 265°C的真空热处理能够将Au_9Ge_1薄膜电极的电阻率降低～50%.本研究工作为降低金锗合金电极的电阻率提供了一种有效的方法.
The gold germanium thin film is an important material for the ohmic electrode of electronic devices. Vacuum thermal treatment is an important method to reduce the contact resistances for ohmic electrodes. In this paper, the relationship between the surface morphology of PVD grown Au_9Ge_1 thin films and their resistances and temperature of vacuum thermal treatment is studied. It is found that when the vacuum thermal treatment temperature reaches 180°C, sporadic dots due to the separation of germanium atoms start to appear on the surface of the film. As temperature increased, the separation of germanium atoms gradually changes from dispersed dots to divergent snowflake shapes. And the electrical resistance of the thin film decreases. When the vacuum thermal treatment temperature reaches 265°C, the minimum resistivity of ～2.0175 Ω/mm of the gold germanium film is achieved. As the vacuum thermal treatment temperature increases further, gold atoms start to agglomerate to form hillocks, and the resistance of the films increase dramatically.The resistivity of the thin film reaches ～6.4×10~5Ω/mm as the thermal treatment temperature reaches 280°C, which is close to power off. Compared with the sample without any thermal treatment, the temperature of vacuum thermal treatment at 265°C can reduce the resistivity of Au_9Ge_1 film electrode by ～50%. This study provides an effective method to reduce the resistivity of gold germanium films in application of ohmic electrodes.
The gold germanium thin film is an important material for the ohmic electrode of electronic devices. Vacuum thermal treatment is an important method to reduce the contact resistances for ohmic electrodes. In this paper, the relationship between the surface morphology of PVD grown Au_9Ge_1 thin films and their resistances and temperature of vacuum thermal treatment is studied. It is found that when the vacuum thermal treatment temperature reaches 180°C, sporadic dots due to the separation of germanium atoms start to appear on the surface of the film. As temperature increased, the separation of germanium atoms gradually changes from dispersed dots to divergent snowflake shapes. And the electrical resistance of the thin film decreases. When the vacuum thermal treatment temperature reaches 265°C, the minimum resistivity of ～2.0175 Ω/mm of the gold germanium film is achieved. As the vacuum thermal treatment temperature increases further, gold atoms start to agglomerate to form hillocks, and the resistance of the films increase dramatically.The resistivity of the thin film reaches ～6.4×10~5Ω/mm as the thermal treatment temperature reaches 280°C, which is close to power off. Compared with the sample without any thermal treatment, the temperature of vacuum thermal treatment at 265°C can reduce the resistivity of Au_9Ge_1 film electrode by ～50%. This study provides an effective method to reduce the resistivity of gold germanium films in application of ohmic electrodes.
引文
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18 Yang B C,Cui H L.Manufacture and application of sputtering target materials.Vacuum,2001,3:11-15
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20 Kim J Y,Hummel R E.Hole and hillock formation in gold metallizations at elevated temperatures deposited on Titanium,Vanadium,and other barrier layers.Phys Stat Sol(A),1990,122:255-273
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26 Chaudhari P.Hillock growth in thin films.J Appl Phys,1974,45:4339-4346
27 Borghi F,Sogne E,Lenardi C,et al.Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing.J Appl Phys,2016,120:055302
28 Chang J,Huang X,Zhou G,et al.Multilayered Si nanoparticle/reduced graphene oxide hybrid as a high-performance lithium-ion battery anode.Adv Mater,2014,26:758-764
29 Kim D,Heiland B,Nix W D,et al.Microstructure of thermal hillocks on blanket Al thin films.Thin Solid Films,2000,371:278-282
30 Bond B G C.The electronic structure of Platinum-Gold alloy particles.Platin Met Rev,2007,51:63-68
2 Zhang Y L.Application and development of precious metal materials for semiconductor-microelectronic technology(in Chinese).Precious Metals,2005,26:49-57[张永俐.半导体微电子技术用贵金属材料的应用与发展.贵金属,2005,26:49-57]
3 Lin H C,Senanayake S,Cheng K Y,et al.Optimization of AuGe-Ni_Au ohmic contacts for GaAs MOSFETs.IEEE Trans Electron Devices,2003,50:880-885
4 Cai X.Reliability Research on Electronic Packaging(in Chinese).Dissertation for Dcotoral Degree.Shanghai:Chinese Academy of Sciences(Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences),2002.33-52[彩霞.高密度电子封装可靠性研究.博士学位论文.上海:中国科学院研究生院(上海微系统与信息技术研究院),2002.33-52]
5 Xu B L.Reliability Research on Electronic Packaging(in Chinese).Dissertation for Dcotoral Degree.Shanghai:Chinese Academy of Sciences(Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences),2002.5-17[徐步陆.电子封装可靠性研究.博士学位论文.上海:中国科学院研究生院(上海微系统与信息技术研究所),2002.5-17]
6 Yang A H,Xie H C.Application of Au-Ge Alloy in electron industry(in Chinese).Precious Metals,2007,28:63-66[阳岸恒,谢宏潮.金锗合金在电子工业中的应用.贵金属,2007,28:63-66]
7 Yang M L,Zhang H X,Yu X M.Fabrication of Au-Ge Ohmic contact(in Chinese).Semicond Infor,2001,38:32-34[杨梦丽,张红欣,于信明.金-锗系统欧姆接触制备研究.微纳电子技术,2001,38:32-34]
8 Lang F Q,Yamaguchi H,Nakagawa H,et al.Solid-state interfacial reaction between eutectic Au-Ge Solder and Cu/Ni(P)/Au metalized ceramic substrate and its suppression.J Mater Sci Tech,2015,31:445-452
9 Xie H C,Yang A H,Zhuang D X,et al.Influence of Ni on microstructure and properties of AuGe12 alloy(in Chinese).Precious Metals,2011,32:35-39[谢宏潮,阳岸恒,庄滇湘,等.Ni对AuGe12合金组织和性能的影响.贵金属,2011,32:35-39]
10 Hu Y F,Li X X,Yu S L.Au eutectic solders welding technology and its application(in Chinese).Electric Welding Machine,2008,38:57-60[胡永芳,李孝轩,禹胜林.基于Au基共晶焊料的焊接技术及其应用.电焊机,2008,38:57-60]
11 Jiang F Y,Liu J L,Wang L,et al.High optical efficiency GaN based blue LED on silicon substrate(in Chinese).Sci Sin-Phys Mech Astron,2015,45:067302[江风益,刘军林,王立,等.硅衬底高光效GaN基蓝色发光二极管.中国科学:物理学力学天文学,2015,45:067302]
12 Kimura N,Sakuma K,Hirafune S,et al.Extrahigh color rendering white light-emitting diode lamps using oxynitride and nitride phosphors excited by blue light-emitting diode.Appl Phys Lett,2007,90:051109
13 Kang B,Ceder G.Battery materials for ultrafast charging and discharging.Nature,2009,458:190-193
14 Ishikawa Y,Sakamoto K,Yamashita S,et al.High-frequency semiconductor device having microwave transmission line being formed by a gate electrode source electrode and a dielectric layer in between.US Patent,US6285269-P,2001-9-4
15 Jiang Y N,Cao X M.The research of eutectic die attachment technology(in Chinese).Semicond Tech,2008,30:53-56[姜永娜,曹曦明.共晶烧结技术的实验研究.半导体技术,2005,30:53-56]
16 Xia H.Film and Precious Metal Targets(in Chinese).In:TFC’03 National Thin Film Technology Symposium Abstracts.Beijing:Chinese Vacuum Society,2003[夏慧.薄膜与贵金属靶材.见:TFC’03全国薄膜技术学术研讨会论文摘要集.北京:中国真空学会,2003]
17 Chen Y,Ma S Y.Study of electroluminescence mechanism in Au/Ge/SiO2nanometer multi-layer films/p-Si structure(in Chinese).J Funct Mater,2007,38:142-143[陈彦,马书懿.Au/锗/氧化硅纳米多层膜/p-Si结构的电致发光机制研究.功能材料,2007,38:142-143]
18 Yang B C,Cui H L.Manufacture and application of sputtering target materials.Vacuum,2001,3:11-15
19 Mu F C,Li Z G.Study and progress of GaAs MESFET ohmic contact(in Chinese).Semicond Tech,1998,5:6-12[穆甫臣,李志国.GaAs MESFET欧姆接触可靠性研究进展.半导体技术,1998,5:6-12]
20 Kim J Y,Hummel R E.Hole and hillock formation in gold metallizations at elevated temperatures deposited on Titanium,Vanadium,and other barrier layers.Phys Stat Sol(A),1990,122:255-273
21 Sauter L,Balk T J,Dehm G,et al.Hillock formation and thermal stresses in thin Au films on Si substrates.In:Mrs Proceedings,Symposium O-Thin Films-Stresses and Mechanical Properties XI.Cambridge:Winter,2005.875
22 Abeles B,Sheng P,Coutts M D,et al.Structural and electrical properties of granular metal films.Adv Phys,2006,24:407-461
23 Gimpl M L,Mcmaster A D,Fuschillo N.Amorphous oxide layers on gold and nickel films observed by electron microscopy.Vacuum,1964,15:3572-3575
24 Thornton J A.High rate thick film growth.Annu Rev Mater Res,1977,7:239-260
25 Wu G,Zeng X,Ding W,et al.Characterization of ceramic PVD thin films on AZ31 magnesium alloys.Appl Surf Sci,2006,252:7422-7429
26 Chaudhari P.Hillock growth in thin films.J Appl Phys,1974,45:4339-4346
27 Borghi F,Sogne E,Lenardi C,et al.Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing.J Appl Phys,2016,120:055302
28 Chang J,Huang X,Zhou G,et al.Multilayered Si nanoparticle/reduced graphene oxide hybrid as a high-performance lithium-ion battery anode.Adv Mater,2014,26:758-764
29 Kim D,Heiland B,Nix W D,et al.Microstructure of thermal hillocks on blanket Al thin films.Thin Solid Films,2000,371:278-282
30 Bond B G C.The electronic structure of Platinum-Gold alloy particles.Platin Met Rev,2007,51:63-68