Low contact resistivity of metal/n-GaN by the reduction of gap states with an epitaxially grown GaOx insulating layer

We investigated the contact properties of metal/n-GaN and metal/GaOx/n-GaN in terms Fermi level pinning (FLP) by metal-induced disorder-induced gap states (MIGS DIGS). The work function ten different metals spanned a wide range from 4.2 to 5.7 eV. measured Schottky barrier height vs metal showed linear relationship with slope parameter S = 0.26 ± 0.01 for doped undoped GaN, indicating strong FLP. insertion GaOx layer increased 0.35 corresponding decrease state density ∼1.1 × 1013 states/(cm2 eV). A resistivity 1.3 10−5 Ω cm2 was obtained Al/GaOx (2.3 nm)/n-GaN (doped 2 1018 cm−3 Si), which smaller nearly three orders than that without layer. insulating property partially epitaxial structure were considered be responsible reduction MIGS DIGS densities, respectively, thereby relaxing FLP leading low resistivity. Optimization growth parameters may further improve property.