共查询到19条相似文献,搜索用时 265 毫秒
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实现SiC器件欧姆接触常规工艺需要800~1200℃的高温退火.研究了n型4H-SiC低温制备Ti欧姆电极的工艺及其基本电学特性.通过氢等离子体处理4H-SiC的表面,沉积Ti后可直接形成欧姆接触,室温下比接触电阻率ρc为2.25×10-3 Ω·m2(ρc由圆形传输线模型CTLM测得),随着合金温度的升高,其欧姆特性逐渐增强,400℃合金后获得最低的比接触电阻率ρc为2.07×10-4 Ω·m2.采用X射线衍射(XRD)确定金属/n-SiC界面反应时形成的相,以分析电学性质与微观结构间的联系.最后讨论了低温欧姆接触的形成机制. 相似文献
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用卢瑟福背散射(RBS)和同步辐射X射线衍射(XRD)研究了p-GaN上的Ni/Au电极在空气下不同温度合金后的微结构的演化,并揭示这种接触结构的欧姆接触形成机制.研究不同温度下比接触电阻(ρc)的变化,发现从450℃开始Au扩散到GaN的表面在p-GaN上形成外延结构以及O向电极内部扩散反应生成NiO对降低ρc起到了关键的作用.在500℃时,Au的外延结构进一步改善,O进一步向样品内部扩散生成NiO,ρc也达到了最低值.但当合金温度升高到600℃时,金属-半导体界面NiO的大部分或全部向外扩散,从而脱离与p-GaN的接触,使ρc显著升高. 相似文献
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利用金属有机化合物化学气相淀积(MOCVD)在SiC衬底上外延生长了N-polar GaN材料,采用传输线模型(TLM)分析了Ti/Al/Ni/Au金属体系在N-polar GaN上的欧姆接触特性.结果表明,Ti/Al/Ni/Au (20/60/10/50 nm)在N-polar GaN上可形成比接触电阻率为2.2×10-3Ω·cm2的非合金欧姆接触,当退火温度升至200℃,比接触电阻率降为1.44×10-3 Ω·cm2,随着退火温度的进一步上升,Ga原子外逸导致欧姆接触退化为肖特基接触. 相似文献
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Ti/Al/Ti/Au与AlGaN欧姆接触特性 总被引:8,自引:4,他引:4
研究了溅射 Ti/ Al/ Ti/ Au四层复合金属与 Al Ga N / Ga N的欧姆接触特性 ,并就环境温度对欧姆接触特性的影响进行了分析研究 .试验证实 :溅射的 Ti/ Al/ Ti/ Au与载流子浓度为 2 .2 4× 10 1 8cm- 3的 Al Ga N之间在室温下无需退火即可形成欧姆接触 .随快速退火温度的升高接触电阻降低 .快速退火时间 30 s已可实现该温度下最佳欧姆接触 .当工作温度不高于 30 0℃时接触电阻几乎不受温度的影响 相似文献
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采用溅射法在液相外延 3 C-Si C上制备 Ni电极 ,并利用圆形传输线法研究了退火温度对欧姆接触特性的影响 ,实验表明对于 Ni/n-Si C金半接触 ,经过 80 0~ 1 0 0 0°C高温退火 5分钟后 ,肖特基整流特性退化为欧姆接触 ,表现出良好的欧姆接触特性 ,且随退火温度的提高 ,接触电阻进一步下降 ,1 0 0 0°C退火后 ,可获得最低的接触电阻为 5 .0× 1 0 - 5Ω· cm2。 相似文献
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氧化Au/Ni/p-GaN欧姆接触形成的机理 总被引:1,自引:0,他引:1
用卢瑟福背散射(RBS)和同步辐射X射线衍射(XRD)研究了p-GaN上的Ni/Au电极在空气下不同温度合金后的微结构的演化,并揭示这种接触结构的欧姆接触形成机制.研究不同温度下比接触电阻(ρc)的变化,发现从450℃开始Au扩散到GaN的表面在p-GaN上形成外延结构以及O向电极内部扩散反应生成NiO对降低ρc起到了关键的作用.在500℃时,Au的外延结构进一步改善,O进一步向样品内部扩散生成NiO,ρc也达到了最低值.但当合金温度升高到600℃时,金属-半导体界面NiO的大部分或全部向外扩散,从而脱离与p-GaN的接触,使ρc显著升高. 相似文献
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This paper describes the ohmic contacts to single-crystalline 3C-SiC thin films heteroepitaxially grown on Si (0 0 1) wafers. In this work, a TiW (titanium-tungsten) film was deposited as a contact material by RF magnetron sputter and annealed through the vacuum and rapid thermal anneal (RTA) process. Contact resistivity between the TiW film and the n-type 3C-SiC substrate was measured by the circular transmission line model (C-TLM) method. The contact phases and interface of the TiW/3C-SiC were evaluated with X-ray diffraction (XRD), scanning electron microscope (SEM) and Auger electron spectroscopy (AES) depth-profiles. The TiW film annealed at 1000 °C for 45 s with the RTA plays an important role in the formation of ohmic contact with the 3C-SiC film and the contact resistance is less than 4.62×10−4 Ω cm2. Moreover, the inter-diffusion at the TiW/3C-SiC interface was not generated during, before and after annealing, and was kept in a stable state. Therefore, the ohmic contact formation technology of single-crystalline 3C-SiC films by using the TiW film is very suitable for high-temperature micro-electro-mechanical system (MEMS) applications. 相似文献
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J. W. Wu C. Y. Chang K. C. Lin E. Y. Chang J. S. Chen C. T. Lee 《Journal of Electronic Materials》1995,24(2):79-82
The thermal stability of ohmic contact to n-type InGaAs layer is investigated. When Ni/Ge/Au is used as the contact metal,
the characteristics of the ohmic contact are degraded after thermal treatment. The specific contact resistance of (Ni/Ge/Au)-InGaAs
ohmic contact after annealing at 450°C is about 15 times larger than that of as-deposited sample. This is due to the decomposition
of InGaAs and the interdiffusion of Ga and Au. A new phase of Au4ln appears after annealing at 300°C. While in the case of Ti/Pt/Au, Au does not penetrate into the InGaAs layer as revealed
by secondary ion mass spectroscopy. The specific contact resistance of (Ti/Pt/Au)-InGaAs ohmic contact after annealing at
450°C is eight times larger than that of as-deposited sample. Therefore, the thermal stability of (Ti/Pt/Au)-InGaAs ohmic
contact is better than that of (Ni/Ge/Au)InGaAs ohmic contact. 相似文献
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V. Q. Ho 《Journal of Electronic Materials》1989,18(4):493-499
In this paper, the physical and electrical properties of a TiNxOy/TiSi2 dual layer contact barrier are reported. The TiNxOy/TiSi2 barrier was formed by rapidly annealing a Ti thin film on Si in an N2 ambient. During this process, the Ti film surface reacts with N2 to form a TiNxOy skin layer and the bulk of the Ti film reacts with Si to form an underlying TiSi2 layer. The influences of rapid thermal anneal (RTA) conditions on the TiNxOy layer were investigated by varying the RTA temperature from 600 to 1100° C and cycle duration from 30 to 100 s. It is found that the resulting TiNxOy and TiSi2 layer thicknesses are dependent on RTA temperature and the starting Ti thickness. For a starting Ti thickness of 500Å, 150Å thick TiNxOy and 800Å thick TiSi2 are obtained after an RTA at 900° C for 30 s. The TiNxOy thickness is limited by a fast diffusion of Si into Ti to form TiSi2. When a Ti film is deposited on SiO2, Ti starts to react with SiO2 from 600° C and a significant reduction of the SiO2 thickness is observed after an RTA at 900° C. The resulting layer is composed of a surface TiNxOy layer followed by a complex layer of titanium oxide and titanium suicide. In addition, when Ti is depos-ited on TiSi2, thicker TiNxOy and TiSi2 layers are obtained after RTA. This is because the TiSi2 layer retards the diffusion of Si from the underlying substrate into the Ti layer. NMOSFETs were fabricated using the TiNxOy/TiSi2 as a contact barrier formed by RTA at 900° C for 30 s and a significant reduction of contact resistance was obtained. In addition, electromigration test at a high current density indicated that a significant improvement in mean time to failure (MTF) has been obtained with the barrier. 相似文献
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Ching-Ting Lee Ming-Yuan Yeh Chang-Da Tsai Yen-Tang Lyu 《Journal of Electronic Materials》1997,26(3):262-265
A bilayer Nd/Al metallization structure has been deposited onto low pressure organometallic vapor phase epitaxy grown n-type
GaN ( 1 × 1018 cm−3) by electron-beam evaporation. Ohmic metal contacts were patterned photolithographically for standard transmission line measurement,
and then thermally annealed at temperatures ranging from 200 to 350°C and from 500 to 650°C using conventional thermal annealing
(CTA) and rapid thermal annealing (RTA), respectively. The lowest values for the specify contact resistivity of 9.8 × 10−6 Ω−cm2 and 8 × 10−6 Ω−cm2 were obtained using Nd/Al metallization with CTA of 250°C for 5 min and RTA of 600°C for 30 s. Examination of the surface
morphology using atomic force microscopy as a function of annealing temperature revealed that the surface roughness was strongly
influenced by conventional thermal annealing, it was smooth in the temperature range from 550 to 650°C for rapid thermal annealing.
Auger electron spectroscopy depth profiling was employed to investigate the metallurgy and interdiffusion of contact formation. 相似文献
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B. P. Luther S. E. Mohney J. M. Delucca R. F. Karlicek Jr. 《Journal of Electronic Materials》1998,27(4):196-199
The annealing conditions and contact resistivities of Ta/Al ohmic contacts to n-type GaN are reported for the first time.
The high temperature stability and mechanical integrity of Ti/Al and Ta/Al contacts have been investigated. Ta/Al (35 nm/115
nm) contacts to n-type GaN became ohmic after annealing for 3 min at 500°C or for 15 s at 600°C. A minimum contact resistivity
of 5×10−6Ω cm2 was measured after contacts were repatterned with an Al layer to reduce the effect of a high metal sheet resistance. Ti/Al
and Ta/Al contacts encapsulated under vacuum in quartz tubes showed a significant increase in contact resistivity after aging
for five days at 600°C. Cross section transmission electron microscopy micrographs and electrical measurements of aged samples
indicate that the increased contact resistivity is primarily the result of degradation of the metal layers. Minimal reactions
at the metal/GaN interface of aged samples were observed. 相似文献
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Dae-Woo Kim Jun Cheol Bae Woo Jin Kim Hong Koo Baik Cha Yeon Kim Wook Kim Yoon Ho Choi Chin-Kyo Kim Tae-Kyung Yoo Chang Hee Hong Sung-Man Lee 《Journal of Electronic Materials》2001,30(7):855-860
We have investigated the electrical properties and interfacial reactions of the Si/Ti-based ohmic contacts to Si-doped n-GaN grown by metal organic chemical vapor deposition and the electrical properties were related to the material reactions. Si/Ti contact system was selected because Ti silicides have a low work function comparable to Al and also Si was used widely as an n-type dopant. As the annealing temperature increased, the specific contact resistance of Si/Ti-based ohmic contacts decreased and showed minimum contact decreased and showed minimum contact resistance as low as 3.86 10?6 cm2 after annealing at 900°C for 3 min under N2 ambient. Our experimental results show that the ohmic behavior of Si/Ti-based contact, were attributed to the low barrier height of Ti-silicide/GaN interface, which was formed through the interfacial reaction between Si and Ti layers. In order to clarify the current conduction mechanism of Si/Ti-based contact, temperature dependent contact resistance measurement was carried out for Au(1000 Å)/Ti(400 Å)/Si(1500 Å)/Ti(150 Å) contact system after annealing at 700°C for 3 min. The contact resistance of Si/Ti-based ohmic contact decreased exponentially with the measuring temperature and so it can be concluded that current flows over the low barrier height by thermionic emission. 相似文献
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The properties of TiN/TiSi2 bilayer formed by rapid thermal annealing (RTA) in an NH3 ambient after the titanium film is deposited on the silicon substrate is investigated. It is found that the formation of
TiN/TiSi2 bilayer depends on the RTA temperature and a competitive reaction for the TiN/TiSi2 bilayer occurs at 600°C. Both the TiN and TiSi2 layers represent titanium-rich films at 600°C anneal. The TiN layer has a stable structure at 700°C anneal while the TiSi2 layer has C49 and C54 phase. Both the TiN and TiSi2 layers have stable structures and stoichiometries at 800°C anneal. When the TiN/TiSi2 bilayer is formed, the redistribution of boron atoms within the TiSi2 layer gets active as the anneal temperature is increased. According to secondary ion mass spectroscopy analysis, boron atoms
pile up within the TiN layer and at the TiSi2−Si interface. The electrical properties for n+ and p+ contacts are investigated. The n+ contact resistance increases slightly with increasing annealing temperature but the p+ contact resistance decreases. The leakage current indicates degradation of the contact at high annealing temperature for
both n+ and p+ junctions. 相似文献
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Ippei Fujimoto Hirokuni Asamizu Masahiro Shimada Miki Moriyama Naoki Shibata Masanori Murakami 《Journal of Electronic Materials》2003,32(9):957-963
To understand formation and deterioration mechanisms of Ta/Ti ohmic contacts that were previously developed for p-GaN, the
electrical properties of the Ta/Ti contacts, which were deposited on undoped GaN substrates and subsequently annealed in vacuum
(where a slash (/) sign indicates the deposition sequence), were studied. The Ta/Ti contacts displayed good ohmic behavior
after annealing at a temperature of 800°C for 10 min in vacuum, although the undoped GaN substrates were used. However, deterioration
of the present ohmic contacts was observed during room-temperature storage. These contact properties were similar to those
observed in the Ta/Ti contacts prepared on p-GaN. Hall-effect measurements revealed that thin n-type conductive layers were
found to form on surfaces of both the undoped GaN and p-GaN substrates after annealing at 800°C in vacuum. 相似文献
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T.K. Tsai S.S. Wu W.L. Liu S.H. Hsieh W.J. Chen 《Journal of Electronic Materials》2007,36(11):1408-1414
In this work, an electroless CoWP film deposited on a silicon substrate as a diffusion barrier for electroless Cu and silicon
has been studied. Four different Cu 120 nm/CoWP/Si stacked samples with 30, 60, 75, and 100 nm electroless CoWP films were
prepared and annealed in a rapid thermal annealing (RTA) furnace at 300°C to 800°C for 5 min. The failure behavior of the
electroless CoWP film in the Cu/CoWP/Si sample and the effect of CoWP film thickness on the diffusion barrier properties have
been investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD),
and sheet resistance measurements. The composition of the electroless CoWP films was 89.4 at.% Co, 2.4 at.% W, and 8.2 at.%
P, as determined by energy dispersive X-ray spectrometer (EDS). A 30 nm electroless CoWP film can prevent copper penetration
up to 500°C, and a 75 nm electroless CoWP film can survive at least up to 600°C. Therefore, increasing the thickness of electroless
CoWP films effectively increases the failure temperature of the Cu/CoWP/Si samples. The observations of SEM and TEM show
that interdiffusion of the copper and cobalt causes the failure of the electroless CoWP diffusion barriers in Cu/CoWP/Si during
thermal annealing. 相似文献