Characterization and reliability of InP-based HEMTs implemented with different process options

In this paper the study of InP based HEMTs implemented with different process options (with or without an InP etch stopper layer, with wide or narrow lateral gate recess regions, with MBE or MOCVD process growth) will be presented. It will be demonstrated that devices with the InP etch stopper layer do not present any kink effects in the output I-V characteristics, neither any transconductance frequency dispersion, gm(f). Furthermore a stable behavior with respect to hot electron aging is observed. The opposite occurs in devices without the InP etch stopper layer, in which kink effects and transconductance frequency dispersion were always observed. Large degradation in the I-V characteristics is observed in these devices after hot electron aging. It must be mentioned however that devices without the InP etch stopper layer and a narrow lateral gate recess region are stable after hot-electron aging and do not present parasitic phenomena. This indicate that kink and gm(f) dispersion closely depends on the material at the surface and to the dimension of the gate recess region.