ALGAN/GAN HEMTS HAVING A GATE CONTACT ON A GAN BASED CAP SEGMENT AND METHODS OF FABRICATING THE SAME

摘要

High electron mobility transistors (HEMTs) and methods of fabricating HEMTs are provided Devices according to embodiments of the present invention include a gallium nitride (GaN) channel layer and an aluminum gallium nitride (AlGaN) barrier layer on the channel layer. A first ohmic contact is provided on the barrier layer (16) to provide a source electrode (18) and a second ohmic contact is also provided on the barrier layer (16) and is spaced apart from the source electrode (18) to provide a drain electrode (20). A GaN-based cap segment (30) is provided on the barrier layer (16) between the source electrode (18) and the drain electrode (20). The GaN-based cap segment (30) has a first sidewall (31) adjacent and spaced apart from the source electrode (18) and may have a second sidewall (32) adjacent and spaced apart from the drain electrode (20). A non-ohmic contact is provided on the GaN-based cap segment (30) to provide a gate contact (22). The gate contact (22) has a first sidewall (27) which is substantially aligned with the first sidewall (31) of the GaN-based cap segment (30). The gate contact (22) extends only a portion of a distance between the first sidewall (31) and the second sidewall (32) of the GaN-based cap segment (30).