Two-step growth of β-Ga2O3 films on (100) diamond via low pressure chemical vapor deposition

One of the major challenges in beta -Ga2O3-based high power and high frequency devices is anticipated to be related to the low thermal conductivity of the material which is on the order of 10-30W/mK. The use of diamond (thermal conductivity similar to 2000W/mK) as a substrate can be one effective approach for achieving better thermal management in beta -Ga2O3-based devices. In this work, low pressure chemical vapor deposition was used to grow beta -Ga2O3 films on (100) oriented, single-crystalline diamond substrates. A two-step growth technique was employed to avoid the oxidation of the diamond surface at high temperatures. From x-ray diffraction measurements, the beta -Ga2O3 films grew along the - 201 crystalline axis with the beta -Ga2O3 (002) planes rotated by +/- 24.3-27 degrees with respect to the diamond (111) planes. High-magnification scanning transmission electron microscopy imaging revealed an abrupt beta -Ga2O3/diamond interface without any voids which is essential for the high rate of heat transfer across the interface. N-type electrical conductivity was measured in a Si-doped beta -Ga2O3 film with 1.4x10(19)cm(-3) electron concentration and similar to 3cm(2)/Vs electron mobility. This work demonstrates the feasibility of heteroepitaxy of beta -Ga2O3 films on diamond substrates for potential device design and device fabrication with efficient thermal management.

Automated summary

In this study, heteroepitaxy of beta -Ga2O3 films on diamond substrates was successfully achieved, demonstrating the feasibility of potential device design and device fabrication with efficient thermal management. The Si-doped beta -Ga2O3 film exhibited N-type electrical conductivity, showcasing the potential for application in high power and high frequency devices. The interface between beta -Ga2O3 and diamond was found to be void-free, essential for high rate of heat transfer across the interface.