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

Wafer bonding of & beta;-Ga2O3 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 Ga2O3/ZnO/N-polar GaN test structure and after annealing at 600 & DEG;C and 1100 & DEG;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 & DEG;C in N-2,N- 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 & beta;-Ga2O3 and GaN achieved in this work is promising to combine the material merits of both GaN and Ga2O3 targeting breakthrough high-frequency and high-power device performances.

Automated summary

Wafer bonding of β-Ga2O3 and N-polar GaN single crystal substrates, achieved by adding ZnO as a glue interlayer, resulted in fully bonded wafers without Newton rings. Temperature-dependent current-voltage measurements revealed the impact of post-annealing temperature on the electrical and structural characteristics of the bonded samples. Annealing the bonded wafers at 1100°C in N-2,N- environment consistently produced ohmic-like characteristics, attributed to the crystallization of ZnO and diffusion of Ga into ZnO. This work demonstrates promising wafer bonding of β-Ga2O3 and GaN, with potential applications in high-frequency and high-power devices.