Embodiments of the disclosure provide an electrostatic discharge (ESD) device, including: an input pad; an underlapped field effect transistor (UL-FET) with a trigger voltage Vt, including: an underlapped drain region coupled to the input pad; a source region coupled to ground; and a gate structure coupled to the input pad; and a blocking layer separating the underlapped drain region from the gate structure of the UL-FET by an underlap distance.