Hahn, H.H.HahnReuters, B.B.ReutersWille, A.A.WilleKetteniss, N.N.KettenissBenkhelifa, FouadFouadBenkhelifaAmbacher, OliverOliverAmbacherKalisch, H.H.KalischVescan, A.A.Vescan2022-03-042022-03-042012https://publica.fraunhofer.de/handle/publica/22844410.1088/0268-1242/27/5/0550042-s2.0-84859311429One current focus of research is the realization of GaN-based enhancement-mode devices. A novel approach for the realization of enhancement-mode behaviour is the utilization of polarization matching between the barrier and the GaN buffer. Yet, the utilization of a quaternary barrier combining polarization engineering together with a large conduction band offset has not been demonstrated so far. Here, epitaxially grown, compressively strained AlInGaN is applied as a nearly polarization-matched barrier layer on GaN resulting in enhancement-mode operation. The insulated-gate devices are fabricated gate-first with Al2O3 as gate dielectric. Passivated metal insulator semiconductor heterostructure field effect transistors yielded threshold voltages (Vth) of up to +1 V. The devices withstand negative and positive gate-biased stress and a positive Vth is maintained even after long-time negative bias stress.en667530journal article