Effects of seed layer thickness and post-annealing process on crystalline quality of 13-Ga2O3 films prepared on Si (100) substrate by RF magnetron sputtering

Ga2O3 films were deposited on Si (100) substrates via radio frequency magnetron sputtering at room tempera-ture. The large lattice mismatch between Ga2O3 and single crystal Si resulted in poor crystalline quality and cracking of the as-deposited Ga2O3 films. To improve the crystalline quality of the Ga2O3 films and promote the combination of Ga2O3 materials with the current Si-based process, a method combining pre-deposited 13-Ga2O3 seed layer and post-annealing process was proposed. Structure, morphology and composition tests showed that when the seed layer was 9 nm and the annealing temperature was 800 degrees C, the prepared film was high crystalline quality 13-Ga2O3 growing along a single (2 01) out-of-plane orientation, and the film thickness was about 160 nm. The seed layer provided nucleation sites for the 13-Ga2O3 films, which alleviated the lattice mismatch between the 13-Ga2O3 films and Si substrates and prevented the film from cracking. In addition, the appropriate annealing temperature could promote the recrystallization of the film, thereby improving the quality of Ga2O3. This work will promote the development of highly integrated and low-cost Ga2O3-based optoelectronic and power devices on Si substrates. In the meantime, it also contributes to solving the problem of poor heat dissipation of Ga2O3 devices.

Automated summary

Ga2O3 films were grown on Si (100) substrates via RF magnetron sputtering at room temperature. The large lattice mismatch led to poor crystalline quality and cracking. To solve this issue, a method combining pre-deposited seed layer and post-annealing process was proposed. The prepared film showed high crystalline quality and thickness of 160 nm when the seed layer was 9 nm and annealing temperature was 800 °C. The seed layer provided nucleation sites and alleviated lattice mismatch, while annealing promoted recrystallization and improved Ga2O3 quality. This work promotes the development of Ga2O3-based devices on Si substrates and solves the heat dissipation problem.