Characterization of Nanoscopic Cu/Diamond Interfaces Prepared by Surface-Activated Bonding: Implications for Thermal Management

Liang, Jianbo; Ohno, Yutaka; Yamashita, Yuichiro; Shimizu, Yasuo; Kanda, Shinji; Kamiuchi, Naoto; Kim, Seongwoo; Koyama, Koji; Nagai, Yasuyoshi; Kasu, Makoto; Shigekawa, Naoteru

doi:10.1021/acsanm.9b02558

Cited by 17 publications

(6 citation statements)

References 44 publications

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“…After annealing at 400 °C, the increased amorphous layer thickness is more helpful in the relaxation of the stress. The amorphous layer thickness increase is unlike the heterointerfaces fabricated by SAB, in which the amorphous layer thickness decreased with increasing annealing temperature due to the recrystallization of the amorphous layer [22][23][24][25][26]. The main difference is no oxygen atoms detected in the SAB-fabricated interface because the bonding processes were conducted in the extremely high-level vacuum condition.…”

Section: Resultsmentioning

confidence: 96%

Room temperature direct bonding of diamond and InGaP in atmospheric air

et al. 2021

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a new technique of diamond and inGaP room temperature bonding in atmospheric air is reported. Diamond substrate cleaned with h 2 sO 4 /h 2 O 2 mixture solution is bonded to inGaP exposed after removing the Gaas layer by the h 2 sO 4 /h 2 O 2 /h 2 O mixture solution. the bonding interface is free from interfacial voids and mechanical cracks. an atomic intermixing layer with a thickness of about 8 nm is formed at the bonding interface, which is composed of c, in, Ga, P, and O atoms. after annealing at 400 °c, no exfoliation occurred along the bonding interface. an increase of about 2 nm in the thickness of the atomic intermixing layer is observed, which plays a role in alleviating the thermal stress caused by the difference of the thermal expansion coefficient between diamond and inGaP. the bonding interface demonstrates high thermal stability to device fabrication processes. this bonding method has a large potential for bonding large diameter diamond and semiconductor materials.

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Section: Resultsmentioning

confidence: 96%

Room temperature direct bonding of diamond and InGaP in atmospheric air

et al. 2021

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“…[ 51,52 ] Reports have shown that the TBR of an as‐bonded Cu/diamond interface with a 4.5 nm‐thick intermediate layer is in good agreement with the value calculated by the phonon diffuse mismatch model. [ 53 ] Furthermore, the TBR of the as‐bonded Si/Si interface fabricated by SAB was found to have a thermal resistance equivalent to that of micrometer‐thick bulk Si. [ 54 ] For the GaN‐on‐diamond structures developed by crystal growth and low‐temperature bonding technologies, the introduction of a transition layer or adhesion layer is essential, but this will result in a double heterogeneous interface.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design

et al. 2021

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The direct integration of gallium nitride (GaN) and diamond holds much promise for high‐power devices. However, it is a big challenge to grow GaN on diamond due to the large lattice and thermal‐expansion coefficient mismatch between GaN and diamond. In this work, the fabrication of a GaN/diamond heterointerface is successfully achieved by a surface activated bonding (SAB) method at room temperature. A small compressive stress exists in the GaN/diamond heterointerface, which is significantly smaller than that of the GaN‐on‐diamond structure with a transition layer formed by crystal growth. A 5.3 nm‐thick intermediate layer composed of amorphous carbon and diamond is formed at the as‐bonded heterointerface. Ga and N atoms are distributed in the intermediate layer by diffusion during the bonding process. Both the thickness and the sp2‐bonded carbon ratio of the intermediate layer decrease as the annealing temperature increases, which indicates that the amorphous carbon is directly converted into diamond after annealing. The diamond of the intermediate layer acts as a seed crystal. After annealing at 1000 °C, the thickness of the intermediate layer is decreased to approximately 1.5 nm, where lattice fringes of the diamond (220) plane are observed.

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“…21(c). Such an intermediate layer, which was a mixture of C and Cu atoms as was confirmed by EDX analysis, 110) could be the origin of thermal stability of interfaces. Using the time domain pulsed-light-heating thermoreflectance technique, 111) the thermal boundary resistance of as-bonded diamond//Cu interfaces (17 ± 2 m 2 • K/GW) was found to be close to that of interfaces prepared by evaporating Cu on-diamond (17 ± 3 m 2 • K/GW).…”

Section: Diamond//si Junctions 101)mentioning

confidence: 64%

Heterojunctions fabricated by surface activated bonding–dependence of their nanostructural and electrical characteristics on thermal process

Shigekawa¹,

Liang²,

Ohno

2022

Jpn. J. Appl. Phys.

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Recent achievements in research of heterojunctions fabricated using surface activated bonding (SAB), one of the practically useful direct wafer bonding technologies, are discussed. The response of bonding interfaces to post-bonding annealing is focused. These junctions reveal high thermal tolerance (1000 ○C in case of junctions made of widegap materials) despite difference in coefficients of thermal expansion between bonded materials. Defect layers with a several-nm thickness formed by the surface activation process at the as-bonded interfaces get faint and their electrical and mechanical properties are improved by annealing. These results show that as bonded interfaces are in a metastable state, and novel functional devices are likely to be realized by applying wafer processing steps to SAB-based junctions. Characteristics of III-V//Si multijunction solar cells, GaN-on-diamond high electron mobility transistors, and metal-foil based low-loss interconnects that are fabricated by processing SAB-based junctions are described, and the future prospects are presented.

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Characterization of Nanoscopic Cu/Diamond Interfaces Prepared by Surface-Activated Bonding: Implications for Thermal Management

Cited by 17 publications

References 44 publications

Room temperature direct bonding of diamond and InGaP in atmospheric air

Room temperature direct bonding of diamond and InGaP in atmospheric air

Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design

Heterojunctions fabricated by surface activated bonding–dependence of their nanostructural and electrical characteristics on thermal process

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