Electrical and Structural Analysis of β‐Ga2O3/GaN Wafer‐Bonded Heterojunctions with a ZnO Interlayer

Abstract Wafer bonding of β ‐Ga 2 O 3 and N‐polar GaN single crystal substrates is demonstrated by adding ZnO as a “glue” interlayer. The wafers are fully bonded such that Newton rings are not observed. Temperature‐dependent current‐voltage ( I – V ) measurements are conducted on the as‐bonded Ga 2 O 3 /ZnO/N‐polar GaN test structure and after annealing at 600 °C and 1100 °C. The impact of post‐annealing temperature on the electrical and structural characteristics of the bonded samples is investigated. A consistently ohmic‐like characteristic is obtained by annealing the bonded wafers at 1100 °C in N 2, which is in part due to crystallization of ZnO and diffusion of Ga into ZnO which makes it n‐type doped. The wafer bonding of β ‐Ga 2 O 3 and GaN achieved in this work is promising to combine the material merits of both GaN and Ga 2 O 3 targeting breakthrough high‐frequency and high‐power device performances.