A monolithic fully-controlled HEMT bidirectional power switch (FC-HEMT BPS) is proposed for the compact and efficient power electronics systems. This device features the segregated Schottky barrier diodes (SBDs) alternately embedded with the segregated p-GaN gate HEMTs in a shared active region. This original device with two independent gate controls realizes four operation modes used for controlling current conduction and voltage blocking arbitrarily. Compared with traditional counterparts, this device not only decreases the turn-on voltage VON-D (0.4 V) of diode mode but also eliminates the turn-on voltage VON-B (0 V) of bidirectional conduction mode.