The present disclosure provides a superjunction based design for normally-OFF HEMT that has two key components: (i) a recessed high-K metal gate and (ii) a superjunction layer under the gate, which is embedded within the N-type GaN buffer layers and separated from recessed gate. Recess gate is to deplete the 2 DEG from the channel region (under the gate) when the transistor is under OFF state. The present disclosure provides a new, improved, efficient and technically advanced HEMT device which can provide higher breakdown voltage, when compared to designs available in the prior-art, without affecting the performance figure of merits. Further, the new HEMT device offers improved breakdown voltage as compared to ON-resistance trade-off, improved the short channel effects, improved gate control over channel, improved switching speed for a given breakdown voltage, and improved device reliability. Furthermore, the new HEMT device lowers gate-to-drain (miller) capacitance and is available at low cost.