Fabrication of n-Si/n-Ga2O3 heterojunctions by surface-activated bonding and their electrical properties.

We studied electrical properties of n-Si/n-Ga₂O₃ heterojunctions fabricated by surface-activated bonding. The energy barrier heights (qϕ_b) at the Si/Ga₂O₃ interface for different reverse voltages (V_rev) were derived from temperature-dependent current density–voltage (J–V–T) characteristics. With shifting V_rev to the negative direction, qϕ_b gradually decreased and reached a constant value due to negatively charged interface states. The conduction band offset at the heterointerface was estimated to be 0.18 eV from the V_rev dependence of qϕ_b. The qϕ_b calculated from a capacitance of the heterojunction at thermal equilibrium was larger than those derived from the J–V–T characteristics, attributing to spatially inhomogeneous qϕ_b caused by the non-uniform distribution of the charged interface states. The density of shallow interface states was also extracted from the reverse J–V–T characteristics, which was estimated to be about 6 × 10¹² cm⁻² eV⁻¹. [ABSTRACT FROM AUTHOR]