Heteroepitaxial growth of α-, β-, γ- and κ-Ga2O3 phases by metalorganic vapor phase epitaxy

Ga2O3polymorphs: tailoring the epitaxial growth conditions

“…Nonetheless, b-Ga 2 O 3 can also be grown using H 2 O at higher T g by properly tuning the growth conditions, and e-Ga without the addition of HCl (which seems to be essential to dissolve GaCl). Nonetheless, a-Ga 2 O 3 was obtained at T 4 760 1C on sapphire using TMG, and N 2 O as an oxidizing agent, and adding boron or nitrogen in the lattice (with triethylboron and dimethylhydrazine) to adjust the mismatch; 70 three monolayers of a-Ga 2 O 3 were always observed at the interface with sapphire before the growth of b-Ga 2 O 3 at 800 1C using TMG and H 2 O. 60 Sun et al 42 reported DFT calculations with the relative energy difference for the formation of different polymorphs between pure Ga 2 O 3 and hydrogenated gallium oxide, due to the introduction of H in the gas phase with HCl (Table 3).…”

Investigating the ranges of (meta)stable phase formation in (InxGa1−x)2O3Wouters1, Sutton2, Ghiringhelli3 et al. 2020Phys. Rev. Materials18071View full textAdd to dashboardCite

“…Additionally, these compounds display a rich phase space, with several polymorphs existing for both Ga 2 O 3 [13,14] and In 2 O 3 [15][16][17][18] that are somewhat higher in energy than the ground-state structures. In Ga 2 O 3 , the α (R3c) [19,20], γ (F d3m) [20,21], and orthorhombic κ (Pna2 1 ) [20,22] (in literature also sometimes referred to as ε phase) phases have all been reported in addition to the thermodynamically stable monoclinic β phase. In addition to the polymorphs of the binary compounds, a hexagonal (h) InGaO 3 alloy phase (see Fig.…”

Structural and Elastic Properties of α‐(AlxGa1−x)2O3 Thin Films on (11.0) Al2O3 Substrates for the Entire Composition Range

“…In comparison to the β‐polymorph, α‐Ga 2 O 3 has a trifle higher bandgap of 5.0–5.3 eV. [ 12–16 ] N‐type conductivity can be achieved by an additional Sn‐doping [ 17 ] enabling the preparation of highly rectifying Schottky barrier diodes. [ 17–19 ] Consequently, devices operating at high voltages with low on‐resistance were already demonstrated.…”

“…Successful fabrication of rhombohedral Ga 2 O 3 was reported by mist chemical vapor deposition (CVD), [ 13,17,19,21–23 ] halide vapor phase epitaxy (HVPE), [ 14,16,24 ] metalorganic vapor phase epitaxy (MOVPE), [ 15 ] mist epitaxy, [ 19 ] and the sol–gel method, [ 12 ] whereas ternary α‐ has been realized by mist CVD, [ 25–28 ] PLD, [ 29,30 ] and molecular beam epitaxy (MBE) [ 31 ] until now. As substrates, a ‐, c ‐, m ‐, or r ‐plane sapphire are possible to use.…”