Fabrication of Substrate-Independent Hybrid Distributed Bragg Reflectors Using Metallic Wafer Bonding

Abstract

A novel hybrid distributed Bragg reflector (DBR) consisting of a substrate-independent amorphous Si-Al-oxide stack and a Cr-Au-Ni-AuGe metallic bonding layer is developed for optoelectronic applications. The metal layers serve as a high-reflectance mirror as well as an adhesion material used in wafer bonding. The hybrid DBR utilizing the reflective metals can achieve a reflectivity of above 99.95% in merely six periods. In addition, the hybrid DBR can adjoin heterogeneous materials at a low temperature of 320°C using a simple metallic bonding process. The hybrid DBR has been successfully applied to the fabrication of 1.55-μm GaInAsP-InP vertical-cavity surface-emitting laser cavities on Si substrates.