AlN/AlGaN/GaN MIS‐HEMTs with recessed source/drain Ohmic contact

Abstract

AlN/AlGaN/GaN MIS‐HEMTs were grown on 4 inch silicon to suppress the gate leakage and achieve high breakdown. However the drain current density maximum obtained is low (361 mA/mm) for 15 μm MIS‐HEMTs. Since the contact resistance of the Ohmic contacts on the insulating AlN is high (5.1 Ωmm), the thin AlN layer was etched prior to the evaporation of the source‐drain Ohmic contact. Though the recessed Ohmic contact reduced the contact resistance to 2.5 Ωmm there is no improvement in the drain current density. The poor quality of the 2 nm AlN growth on silicon could be the possible reason behind the low drain current density. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)