Room temperature bonding of GaN and diamond substrates via atomic layer

GaN and diamond substrates were bonded at room temperature with an atomically thin bonding layer. This entailed sputter etching the surface of the GaN substrate in the bonding machine to expose the active nascent GaN surface. At the same time, rather than using sputter etching, a ∼1 nm-thick Si nano-adhesion layer was deposited on the diamond surface. The advantage of this newly developed approach is that it suppresses the physical damage typically inflicted upon the diamond crystals by sputtering. This restricts the thickness of the amorphous layer at the GaN/diamond bonding interface to less than 2 nm. The proposed GaN/diamond integration is expected to contribute to efficient heat dissipation and facilitate the high-power and high-frequency operation of GaN devices.