Selenium sulfide (SeS2) passivated GaAs is bonded with silicon substrate at 350degreesC. X-ray diffraction (XRD) analysis shows the formation of Ga-Se phase in the passivation process. From the XRD analysis, beta-Ga2Se3 peak is also observed for the chemical and thermal stability of GaAs at 350degreesC. Scanning electron microscopy (SEM) shows smooth surface morphology for SeS2 treatment time of 10 s. Elemental analysis shows that 10 s passivation treatment is optimal for adhesive wafer bonding without applying any weight and pressure at different regions (GaAs and SeS2). XRD, SEM and energy dispersive X-ray results confirm that 10 s of passivation treatment is essential for high stability of adhesive wafer bonding of GaAs and Si. (C) 2003 Elsevier B.V. All rights reserved.