Study on the mechanism of glass-SiC-glass anodic bonding process

Abstract

The connection of silicon carbide (SiC) to glass is important for the development of microelectromechanical systems. In the study, glass-SiC-glass with SiC as common anode was effectively bonded by using anodic bonding technology in atmosphere. The interfacial microstructure of bonded joints was analyzed by using scanning electron microscope, energy-dispersive spectrometer and transmission electron microscope. The effect of the bonding voltages and bonding temperatures on the interfacial microstructure and mechanical property of glass/SiC/glass was investigated. The results indicated that a Na+ depletion layer formed in the glass adjacent to the SiC/glass interface due to the decomposition of Na2O compound in the glass and the migration of Na+ towards the upper surface of glass during anodic bonding. With elevating bonding temperatures or bonding voltages, the thickness of Na+ depletion layer was gradually increased and more O2− accumulated at the SiC/depletion layer interface, which was beneficial for the tensile strength of joints. But owing to the increased residual thermal stress, the tensile strength of the joints dropped with enhanced bonding temperature. The maximum tensile strength of the joint was about ∼12.8 MPa when bonding at 450 °C/1000 V/1 min. The joint mainly ruptured in the glass with a brittle fracture mode.