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First polarization-engineered compressively strained AlInGaN barrier enhancement-mode MISHFET

: Hahn, H.; Reuters, B.; Wille, A.; Ketteniss, N.; Benkhelifa, F.; Ambacher, O.; Kalisch, H.; Vescan, A.


Semiconductor Science and Technology 27 (2012), No.5, Art. 055004, 6 pp.
ISSN: 0268-1242
ISSN: 1361-6641
Journal Article
Fraunhofer IAF ()

One 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.