Effect of Amorphous Layer at the Heterogeneous Interface on the Device Performance of beta-Ga2O3/Si Schottky Barrier Diodes

Heterogeneous integration of beta-Ga2O3 with Si substrate is considered as an effective and low-cost technology for the thermal management of beta-Ga2O3 electrical devices. In this work, an isotype heterojunction of n-Ga2O3/n(+)-Si (Ga2O3/Si) was fabricated by surface activated bonding in which an amorphous layer was induced by ion beam bombardment. The current density of Ga2O3/Si Schottky barrier diodes (SBDs) are about two orders of magnitude lower than that of Ga2O3 bulk SBDs at 2.8 V due to the influence of amorphous layer. The results are consistent with the simulation results when beta-Ga2O3 Mole Fraction (MF = n(beta-Ga2O3)/[n(beta-Ga2O3) + n(SiO2)]) and thickness of amorphous layers (Tox) are set at 0.83 and 3 nm, respectively. Furthermore, devices with different MF and Tox were simulated based on the nonlocal tunneling model by Sentaurus TCAD. The decrease of beta-Ga2O3 Mole Fraction and increase of amorphous layers thickness in the hetero-interface of Ga2O3/Si SBDs lead to a dramatic degeneration of current density and specific on-resistance in Ga2O3/Si SBDs. These results may provide some guidance for improvement of vertical heterogeneous integration beta-Ga2O3 devices performance.