Conductive Semiconductor Interfaces Fabricated by Room Temperature Covalent Wafer Bonding

Abstract

Low temperature direct bonding in the range of maximum 400°C opened an entirely new applications field as it allowed for the direct bonding of wafers with metallization (e.g CMOS) while maintaining a high alignment accuracy as well as bonding of thermally mismatched materials. Despite the clear benefits of the low temperature direct bonding process, the requirements of some categories of applications in terms of allowing for room temperature covalent bonding or oxide-free, electrically conductive interfaces fabrication cannot be fulfilled. A new technology was developed to address these types of applications: EVG®580 Combond®. This paper reports on fabrication of oxide-free, electrically conductive Si-Si and Si-GaAs bonded interfaces based on the newly developed technology. Experimental results on bonding quality and electrical performance of the bonded interfaces are presented.