Material Properties of <i>n</i>‐Type β‐Ga<sub>2</sub>O<sub>3</sub> Epilayers with In Situ Doping Grown on Sapphire by Metalorganic Chemical Vapor Deposition
Fu‐Gow Tarntair, Chih‐Yang Huang, Siddharth Rana, Kun‐Lin Lin, Shao‐Hui Hsu, Yu‐Cheng Kao, Singh Jitendra Pratap, Yi‐Che Chen, Niall Tumilty, Po−Liang Liu, Ray‐Hua Horng
Abstract
Abstract 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.