Doctor of Philosophy, The Ohio State University, 2021, Electrical and Computer Engineering

This dissertation focuses on the development of chemical vapor deposition (CVD) of β-Ga2O3, an ultra-wide bandgap (UWBG) semiconductor representing one of the most promising semiconducting materials for next generation power electronics. Here, two types of CVD thin film deposition techniques were investigated, including the metalorganic chemical vapor deposition (MOCVD) and the low pressure chemical vapor deposition (LPCVD) methods. The main goal of this work aims to establish the fundamental understanding of this emerging UWBG semiconductor material through comprehensive mapping of the growth parameters combined with extensive material characterization. β-Ga2O3, with an ultra-wide bandgap of 4.5-4.9 eV and capability of n-doping, promises its applications for high power electronics. β-Ga2O3 is predicted to have a high breakdown field (~ 8 MV/cm) with room temperature mobility of ~200 cm2/Vs. The Baliga figure of merit (BFOM) of β-Ga2O3 for power electronics is predicted to be 2 to 3 times higher than that of GaN and SiC. One key advantage for β-Ga2O3 is from its availability of high quality and scalable native substrates synthesized via melt growth methods, which is critical to large-scale production with low cost. Thus, this UWBG material has great potential for future generation high power electronics as well as deep ultraviolet optoelectronics. The MOCVD growth window was explored for β-Ga2O3 thin films grown on native Ga2O3 substrates. Group IV Si was identified as an effective n-type dopant with a wide doping range from 1016-1020 cm-3. Under optimized growth conditions, β-Ga2O3 thin films grown on semi-insulating Fe-doped (010) Ga2O3 substrates demonstrated superior room temperature carrier mobilities of 184 and 194 cm2/V·s with and without intentional Si doping at charge concentration of 2.7×1016 cm-3 and 8.5×1015 cm-3, respectively. Temperature-dependent Hall measurements revealed a peak mobility of ~ 9500 cm2/V·s with extremely low compensation concen (open full item for complete abstract)

Committee: Hongping Zhao (Advisor); Steven Ringel (Committee Member); Siddharth Rajan (Committee Member); Hwang Jinwoo (Committee Member); Patrick Woodward (Committee Member) Subjects: Electrical Engineering; Materials Science