High power and high gain AlGaN/GaN MIS‐HEMTs with high‐k dielectric layer

High power n‐GaN/n‐AlGaN/GaN metal‐insulator‐semi‐conductor high electron mobility transistors (MIS‐HEMTs) with high‐k Ta 2 O 5 dielectric layer were fabricated on a 3‐inch S.I.‐SiC substrate, for the first time. An n‐GaN/n‐AlGaN/GaN MIS‐HEMTs with 400 V breakdown voltage were obtained by using Ta 2 O 5 insulating layer/n‐GaN capstructure. The single‐chip GaN MIS‐HEMTs amplifier with a Ta 2 O 5 layer operated at 50 V achieve a high output power of 113 W with a linear gain of 16.3 dB at 2.5 GHz. We also investigated the RF stress reliability under the P3dB condition. The fluctuation of output power and drain current was lower than 5% even after 150 h stress test. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)