Influence of the side-Ohmic contact processing on the polarization Coulomb field scattering in AlGaN/AlN/GaN heterostructure field-effect transistors

Abstract

Using the measured capacitance-voltage curves of Ni Schottky contacts with different areas and the current-voltage characteristics for the circular and rectangular AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with the side-Ohmic contacts, it is found that the polarization Coulomb field scattering caused by the polarization charge density variation at the AlGaN/AlN/GaN interfaces is closely related to the Ohmic-contact processing, and the side-Ohmic contact processing greatly weakens the polarization Coulomb field scattering in the AlGaN/AlN/GaN HFETs.