【Member Papers】Effect of the VI/III ratio on the growth of κ-Ga₂O₃ films via MOCVD

      Researchers from the Nanjing University of Posts and Telecommunications, have published a research paper titled "Effect of the VI/III ratio on the growth of κ-Ga₂O₃ films via MOCVD" in Applied Physics Letters.

Abstract

      The intrinsic spontaneous polarization of orthorhombic κ-Ga₂O₃ offers unique functionalities for advanced devices, yet a processing window for growing the pure κ-phase remains elusive. Herein, the effect of the oxygen-to-gallium precursor molar ratio (VI/III ratio) on the quality of κ-Ga₂O₃ films was systematically investigated via metal-organic chemical vapor deposition. Increasing the VI/III ratio from 500 to 1000 induced a transformation from an amorphous film to a mixed-phase layer containing both β- and κ-Ga₂O₃. At an optimized VI/III ratio of 2000, the competing β-phase was effectively inhibited. Concurrently, the resulting κ-Ga₂O₃ film demonstrated superior quality, with a low rocking curve FWHM of 0.66°, fewer oxygen vacancy defects, and reduced residual carbon. A continuous increase in the VI/III ratio beyond 2000, however, led to the recurrence of the β-phase. Furthermore, this phase evolution behavior during Ga₂O₃ growth is consistent with predictions from heteroepitaxial growth dynamics and classical nucleation theory. The establishment and elucidation of these critical parameters enable a viable route toward growing high-quality, single-phase κ-Ga₂O₃.

DOI：

doi.org/10.1063/5.0288203