Carbide forming interlayers, such as amorphous silicon nitride, are typically used for GaN-on-diamond heterogenous integration. This interlayer has a low thermal conductivity, introducing an additional extrinsic interfacial thermal resistance. It may therefore be advantageous to omit this layer, directly bonding GaN-to-diamond (van der Waals bond). However, weakly bonded interfaces are known to increase the intrinsic thermal boundary resistance. An adapted acoustic mismatch model has been implemented to assess which bonding approach is the most optimal for low thermal resistance GaN-on-diamond. A high thermal boundary resistance of 200 m2 K GW−1 is predicted for weakly bonded GaN-to-diamond interfaces, which is close to the measured value of 220 ± 70 m2 K GW−1, and ∼7× higher than values measured when a 10’s nm-thick SiN interlayer is included. Covalently bonded interfaces are therefore critical for achieving low thermal resistance GaN-on-diamond.

中文翻译：

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直接范德华键合金刚石基氮化镓的热边界电阻

碳化物形成中间层，例如非晶氮化硅，通常用于金刚石上 GaN 异质集成。该夹层具有低热导率，引入了额外的外在界面热阻。因此，省略该层可能是有利的，直接将 GaN 键合到金刚石（范德华键）。然而，已知弱结合界面会增加固有热边界电阻。已实施经过调整的声学失配模型，以评估哪种键合方法最适合低热阻金刚石基氮化镓。对于弱结合的 GaN-金刚石界面，预计具有 200 m2 K GW-1 的高热边界电阻，这接近于 220 ± 70 m2 K GW-1 的测量值，并且比当测量值高约 7 倍时包括一个 10 纳米厚的 SiN 中间层。