Over 6 μm thick MOCVD-grown low-background carrier density (10¹⁵ cm⁻³) high-mobility (010) β-Ga₂O₃ drift layers

This work reports high carrier mobilities and growth rates simultaneously in low unintentionally doped (UID) (10¹⁵ cm⁻³) metalorganic chemical vapor deposition (MOCVD)-grown thick β-Ga₂O₃ epitaxial drift layers, with thicknesses reaching up to 6.3 μm, using triethylgallium (TEGa) as a precursor. Record-high room temperature Hall mobilities of 187–190 cm²/V s were measured for background carrier density values of 2.4–3.5 × 10¹⁵ cm⁻³ grown at a rate of 2.2 μm/h. A controlled background carrier density scaling from 3.3 × 10¹⁶ to 2.4 × 10¹⁵ cm⁻³ is demonstrated, without the use of intentional dopant gases such as silane, by controlling the growth rate and O₂/TEGa ratio. Films show smooth surface morphologies of 0.8–3.8 nm RMS roughness for film thicknesses of 1.24–6.3 μm. Vertical Ni Schottky barrier diodes (SBDs) fabricated on UID MOCVD material were compared with those fabricated on hydride vapor phase epitaxy material, revealing superior material and device characteristics. MOCVD SBDs on a 6.3 μm thick epitaxial layer show a uniform charge vs depth profile of ∼ 2.4 × 10¹⁵ cm⁻³, an estimated μ_drift of 132 cm²/V s, breakdown voltage (V_BR) close to 1.2 kV, and a surface parallel plane field of 2.05 MV/cm without any electric field management—setting record-high parameters for any MOCVD-grown β-Ga₂O₃ vertical diode to date.