Material Properties of n ‐Type β‐Ga 2 O 3 Epilayers with In Situ Doping Grown on Sapphire by Metalorganic Chemical Vapor Deposition

In this study, in situ, Si‐doped heteroepitaxial Ga 2 O 3 layers are grown on c ‐plane sapphire by metalorganic chemical vapor deposition. The X‐ray diffraction peaks of the doped Ga 2 O 3 epilayers shows ß‐phase of Ga 2 O 3 ,and full width at half maximum of Ga 2 O 3 crystallinity is decreased at a Tetraethoxysilane (TEOS) molar flow rate of 2.23 × 10 −7 mol min −1 but increased with higher flow rates. The dopant concentrations of Ga 2 O 3 grown at 825 °C with TEOS molar flows of 2.23 × 10 −7 , 4.47 × 10 −7 , and 6.69 × 10 −7 mol min −1 are measured to be 5.5 × 10 19 , 1.1 × 10 20 , and 1.4 × 10 20 atom cm −3 , respectively, using secondary ion mass spectra and Hall measurements reveal n ‐type nature with carrier concentrations of 6.5 × 10 17 , 3.2 × 10 18 , and 3.9 × 10 18 atom/cm 3 , respectively. To increase Si dopant activation, Ga 2 O 3 growth temperature is raised to 875 °C. The result suggests a higher growth temperature can contribute to a greater probability of Si substitution on Ga lattice sites, which further reduces the resistivity of Ga 2 O 3 epilayer. Moreover, results are compared with theoretical Density Functional Theory studies.