Electrical performance study of Schottky barrier diodes using ion implanted β-Ga2O3 epilayers grown on sapphire substrates

Abstract

β-Ga2O3 epilayers with a 210 nm thickness were successfully grown on c-plane sapphire substrate by metalorganic chemical vapor deposition (MOCVD). Highly resistive unintentionally doped (UID) epilayers are studied, as are Si ion-implantated samples with doses of 1✕1014, 6✕1014 and 1✕1015 cm−2 at 30 keV to improve β-Ga2O3 epilayer conductivity. Schottky barrier diodes (SBDs) were fabricated using optimized growth parameters and electrical measurements performed for both UID and Si-implanted β-Ga2O3 material. The forward current density (J) of an UID SBD at 2 V was 62 nA/cm2 with breakdown voltage (Vbr) of 1.03 kV and leakage J of 10 μA/cm2. The forward J improved by eight orders of magnitude after Si implantation. In this case, Vbr reduced to 680 V combined with a high leakage J of ∼A/cm2 for doses of 1✕1015cm−2. A hard breakdown of 553 V was achieved with a Si-ion dose of 1✕1014 cm−2 with comparatively less leakage than samples with higher dose amounts.

Keywords

• Unintentionally doped (UID) β-Ga2O3 epilayers
• Schottky barrier diodes (SBDs)
• Rapid thermal annealing (RTA)
• Atomic force microscopy (AFM)
• Schottky (S)
• Ohmic (O) contacts