We report on comparison studies between a novel transistor-like device and two dimensional Fin Field-effect transistor (2DEG FinFET) towards their applications in a THz resonant detector. Both device structures have been fabricated on the same wafer of GaN/AlGaN epistructure during one processing run. The proposed here the transistor-like structure has two side Schottky gates, which can be biased towards complete pinch-off the 2DEG channel in this device. The characteristic dimensions of all device structures are in the range of typical for the laser writer processing i.e. a few micrometers, however in the case of the transistor-like device we report on electronical tuned confinement, which works down to submicron range. At certain conditions, near to pinch-off region, it is possible to obtain one dimensional current flow. This feature is especially attractive for THz resonant detector approach, which will be discussed in details.