Integration of GaN thin films to SiO2-Si(100) substrates by laser lift-off and wafer fusion method

摘要

A process methodology has been adopted to bond GaN thin films to Si(100) substrates using the combination of laser lift-off and direct wafer fusion. Using optimum excimer laser conditions, 2-10 mu m of GaN is lifted-off from sapphire. The lifted-off thin film is cleared from gallium residual and then suitably treated in a hydrofluoric, nitric and acetic acid mixture to render the surface hydrophilic. This treatment provides van der Waals bonds to immediately contact bond with SiO2-Si(100) Substrate at room temperature. The bonds are further strengthened by a high temperature annealing at 650 degrees C for 2 It. The structural and mechanical characteristics of the bonded structure reveal uniform and high quality bonding. The optical characteristics of the transferred bonded film on SiO2-Si(100) substrate exhibit similar properties to that of GaN on sapphire. In a similar manner, high-brightness blue LEDs were transferred from sapphire to SiO2-Si(100) substrate with no deterioration in the electrical and optical performance of the device. (c) 2006 Published by Elsevier Ltd