2025/11/11 by Saleh Ahmed Khan, Khan, Saleh Ahmed, Stephen Margiotta +5
Materials Science · Physics and Astronomy · #Ga2O3 and related materials #Semiconductor materials and interfaces #Electronic and Structural Properties of Oxides
paper · pdf · doi:10.48550/arxiv.2511.08758
The integration of diamond with β-Ga2O3 presents a promising pathway to enhance thermal management in high-power electronic devices, where the inherently low thermal conductivity of β-Ga2O3 can lead to localized self-heating and elevated junction temperatures. In this work, we demonstrate a scalable, low-damage approach for integrating polycrystalline diamond films on (010) β-Ga2O3 substrates via microwave plasma chemical vapor deposition (MPCVD), employing dielectric interlayers and polymer-assisted electrostatic nanodiamond seeding to systematically evaluate the impact of growth conditions on film morphology, grain evolution, phase purity, and optical characteristics. At a growth temperature of 800^∘C, progressive grain coarsening is observed with extended deposition, with the lateral grain size increasing from 37.6 nm (53 nm thickness) to 192.5 nm for an 886 nm-thick film. This microstructural evolution is accompanied by narrowing of the diamond Raman peak and a monotonic increase in the sp3 phase fraction from 95.9% to as high as 98.9%, indicating continued suppression of non-diamond carbon with prolonged growth. Comparison of SiO2 and SiNx interlayers under identical growth conditions shows only marginal differences in grain size and phase purity, indicating limited interlayer influence once a high nucleation density is established. Importantly, diamond films exhibiting greater than 96% sp3 phase content were achieved at substrate temperatures as low as 480^∘C, highlighting the viability of diamond-on-Ga2O3 integration under reduced thermal budgets. These findings establish a robust and scalable platform for integrating diamond on β-Ga2O3, supporting the development of next-generation power and RF devices with improved thermal management.