An ultra-thin SiO2 ALD layer for void-free bonding of III–V material on silicon

•An ALD SiO2 layer is proposed for InP on Si bonding.•The ALD SiO2 layer activation with hydroxyl groups is measured by XPS.•The ALD SiO2 layer activation is evidenced by bonding an InP membrane on Si at 300 °C.

Hybrid bonding of III–V layers on silicon is demonstrated implementing an ultra-thin SiO2 atomic layer deposited – ALD – layer as the intermediate bonding layer. X-ray photoelectron spectroscopy characterization of the SiO2 layers evidences that the plasma enhanced – PE – ALD process activates the surfaces with OH dangling bonds. These dangling bonds ensure the surface activation which is necessary for oxide-mediated bonding. The optimized ALD process parameters have been established in order to produce a void-free InP/Si hybrid interface. This hybrid interface is structurally and mechanically characterized. ALD processing is of great interest for hybrid bonding on Si since it offers simultaneously three advantages: a very thin and controlled thickness, an activated surface and a conformal deposition when already patterned silicon layers have to be considered within operating devices.

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