Direct Wafer Bonding of SiC-SiC at Room Temperature by SAB Method

Abstract

In this work, direct wafer bonding of SiC-SiC was accomplished by surface activated bonding (SAB) method at room temperatrue. The bonding energy of ~1.4 J/m2 was obtained without orientation dependence, which is much weaker than bulk SiC strength. Correspondingly, the tensile strength of bonding interface is ~12.2 MPa. The bonding mechanisms were investigated through Monte Carlo simulation and interface analysis by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). The formation of amorphous SiC during surface activation may eliminate the affects of orientation on bonding. In addition, the possible Si preferentially sputtering during surface activation is assumed to be the reason why direct wafer bonding of SiC-SiC cannot reach bulk SiC strength. After a rapid thermal annealing at 1273 K for 180 s in Ar, the tensile strength of bonding interface could be improved to the values higher than 21.6 MPa.