Improved Heat Treatment for Wafer Direct Bonding between Semiconductors and Magnetic Garnets

Abstract
The optical propagation loss of rib waveguides fabricated on magnetic garnet films increased upon annealing in H2 ambient during wafer direct bonding. The heat treatment in wafer direct bonding between InP and Gd3Ga5O12 was investigated with the aim of circumventing the loss increase. The bonding was achieved by heat treatment in H2 ambient at temperatures of ≦330° C or in N2 ambient.