Thermal stability of β-Ga2O3in mixed flows of H2and N2

The thermal stability of β-Ga 2 O 3 (010) substrates was investigated at atmospheric pressure between 250 and 1450 °C in a flow of either N 2 or a mixture of H 2 and N 2 using a radio-frequency induction furnace. The β-Ga 2 O 3 surface was found to decompose at and above 1150 °C in N 2 , while the decomposition of β-Ga 2 O 3 began at only 350 °C in the presence of H 2 . Heating β-Ga 2 O 3 substrates in gas flows containing different molar fractions of H 2 demonstrated that the decomposition was promoted by increasing the H 2 molar fractions. Thermodynamic analysis showed that the dominant reactions are in N 2 and in a mixed flow of H 2 and N 2 . The second-order reaction with respect to H 2 determined for the mixed flows agrees with the experimental results for the dependence of the β-Ga 2 O 3 decomposition rates on the H 2 molar fraction.