A comparison study: Direct wafer bonding of SiC–SiC by standard surface-activated bonding and modified surface-activated bonding with Si-containing Ar ion beam

Mu, Fengwen; Iguchi, Kenichi; Nakazawa, Hiroyuki; Takahashi, Yoshikazu; Fujino, Masataka; He, Rujie; Suga, Tadatomo

doi:10.7567/apex.9.081302

Cited by 39 publications

(33 citation statements)

References 28 publications

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“…A modified SAB method with a sputtering-deposited Si nano-layer is used to bond the CVD diamond (Samp1) and a modified SAB method with Si-containing Ar ion beam is used to bond the HPHT diamond (Samp2). The detailed bonding process are similar to literature 25,50 . After bonding, the sapphire substrate was removed by a laser lift-off process.…”

Section: Four-phonon Scattering Process Which Is Not Included In the mentioning

confidence: 84%

Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices

Cheng

Yates

et al. 2020

ACS Appl. Mater. Interfaces

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137

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The wide bandgap, high-breakdown electric field, and high carrier mobility makes GaN an ideal material for high-power and high-frequency electronics applications such as wireless communication and radar systems. However, the performance and reliability of GaN-based high electron mobility transistors (HEMTs) are limited by the high channel temperature induced by Joule-heating in the device channel. High thermal conductivity substrates (e.g., diamond) integrated with GaN can improve the extraction of heat from GaN-based HEMTs and lower the device operating temperature. However, heterogeneous integration of GaN with diamond substrates is not trivial and presents technical challenges to maximize the heat dissipation potential brought by the diamond substrate. In this work, two modified room-temperature surface-activated bonding (SAB) techniques are used to bond GaN and single crystal diamond with different interlayer thicknesses. Time-domain thermoreflectance (TDTR) is used to measure the thermal properties from room temperature to 480 K. A relatively large thermal boundary conductance (TBC) of the GaN-diamond interfaces with a ~4-nm interlayer (~90 MW/m 2 -K) was observed and material characterization was performed to link the structure of the interface to the TBC. Device modeling shows that the measured GaN-diamond TBC values obtained from bonding can enable high power GaN devices by taking the full advantage of the high thermal conductivity of single crystal diamond and achieve excellent cooling effect. Furthermore, the room-temperature bonding process in this work do not induce stress problem due to different coefficient of thermal expansion in other high temperature integration processes in previous studies. Our work sheds light on the potential for room-temperature heterogeneous integration of semiconductors with diamond for applications of electronics cooling especially for GaN-on-diamond devices.

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Section: Four-phonon Scattering Process Which Is Not Included In the mentioning

confidence: 84%

Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices

Cheng

Yates

et al. 2020

ACS Appl. Mater. Interfaces

Self Cite

137

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“…At the interface, a bright seamless intermediate layer of about 8 nm should be amorphous because it has no lattice fringes and is distinct from adjacent crystalline phase. From data by previous studies, amorphous layer formation was caused by Ar-FAB bombardment [ 29 , 30 ]. Accordingly, EDX liner mapping of Si, C and O elements distribution of a small sample is shown in Figure 5 b, the analysis location and range are roughly shown as the yellow dotted line in Figure 5 a.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of SiC Sealing Cavity Structure for All-SiC Piezoresistive Pressure Sensor Applications

et al. 2020

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High hardness and corrosion resistance of SiC (silicon carbide) bulk materials have always been a difficult problem in the processing of an all-SiC piezoresistive pressure sensor. In this work, we demonstrated a SiC sealing cavity structure utilizing SiC shallow plasma-etched process (≤20 μm) and SiC–SiC room temperature bonding technology. The SiC bonding interface was closely connected, and its average tensile strength could reach 6.71 MPa. In addition, through a rapid thermal annealing (RTA) experiment of 1 min and 10 mins in N2 atmosphere of 1000 °C, it was found that Si, C and O elements at the bonding interface were diffused, while the width of the intermediate interface layer was narrowed, and the tensile strength could remain stable. This SiC sealing cavity structure has important application value in the realization of an all-SiC piezoresistive pressure sensor.

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“…There is a seamless amorphous layer with a thickness of ~15 nm at the bonding interface of SiC-AlN. According to our previous researches [26,27], the surface activation of ion beam bombardment will cause the formation of amorphous layer. Therefore, the amorphous layer may consist of amorphous SiC, amorphous AlN, and deposited Si layer.…”

Section: Resultsmentioning

confidence: 99%

“…For bonding demonstration, a crystalline AlN film with a thickness of ~100 nm and an RMS surface roughness less than ~0.7 nm was deposited on a SiC wafer by a pulsed direct current magnetron sputtering method at a substrate temperature of 973 K. Both standard SAB and modified SAB with Si nano-layer sputtering deposition were applied to the SiC-AlN bonding at room temperature. Standard SAB failed in the bonding, while the bonding using modified SAB had a bonding energy of ~1.6 J/m 2 , which is strong enough to withstand common mechanical cutting process [27]. The microstructure and composition of the bonding interface were investigated by STEM and EELS.…”

Section: Discussionmentioning

confidence: 99%

Wafer Bonding of SiC-AlN at Room Temperature for All-SiC Capacitive Pressure Sensor

Yang

Shin

et al. 2019

Micromachines

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Wafer bonding of a silicon carbide (SiC) diaphragm to a patterned SiC substrate coated with aluminum nitride (AlN) film as an insulating layer is a promising choice to fabricate an all-SiC capacitive pressure sensor. To demonstrate the bonding feasibility, a crystalline AlN film with a root-mean-square (RMS) surface roughness less than ~0.70 nm was deposited on a SiC wafer by a pulsed direct current magnetron sputtering method. Room temperature wafer bonding of SiC-AlN by two surface activated bonding (SAB) methods (standard SAB and modified SAB with Si nano-layer sputtering deposition) was studied. Standard SAB failed in the bonding, while the modified SAB achieved the bonding with a bonding energy of ~1.6 J/m2. Both the microstructure and composition of the interface were investigated to understand the bonding mechanisms. Additionally, the surface analyses were employed to confirm the interface investigation. Clear oxidation of the AlN film was found, which is assumed to be the failure reason of direct bonding by standard SAB.

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A comparison study: Direct wafer bonding of SiC–SiC by standard surface-activated bonding and modified surface-activated bonding with Si-containing Ar ion beam

Cited by 39 publications

References 28 publications

Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices

Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices

Fabrication of SiC Sealing Cavity Structure for All-SiC Piezoresistive Pressure Sensor Applications

Wafer Bonding of SiC-AlN at Room Temperature for All-SiC Capacitive Pressure Sensor

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