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Direct bonding of germanium and diamond substrates by hydrophilic bonding

MetadataDetails
Publication Date2023-04-19
AuthorsYuki Minowa, Takashi Matsumae, Masanori Hayase, Yuichi Kurashima, Hideki Takagi
InstitutionsTokyo University of Science, National Institute of Advanced Industrial Science and Technology
Citations2

Germanium (Ge) is attracting attention as a high-frequency device material, but its low thermal conductivity causes a heat dissipation problem. To overcome this drawback, we demonstrate the direct bonding of the Ge substrate with a diamond heat-dissipating substrate, which has the highest thermal conductivity among solids. The Ge substrate was activated by oxygen plasma, and the diamond substrate was washed with a mixture of NH <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/inf> /H <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/inf> O <inf xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/inf> , and then the two substrates were brought into contact with each other. The substrates were then heated at 200°C for 2 hours with a bond load of 3 MPa. The above process resulted in the direct bonding of the Ge and diamond substrates. This direct bonding improves the heat dissipation of Ge devices, which will contribute to next-generation high-speed devices.