An electrostatic discharge (ESD) protection device implemented in finFET technology is disclosed. The device has a reduced thickness shallow trench isolation (STI) layer which allows migration of high-doped drain implants therethrough to form regions extending under the STI layer thereby creating a planar-like region under the STI layer. Further, the regions are formed in an n-well layer provided between a substrate and the STI layer. The formation of the planar-like region under the STI layer has the advantage that part of the thermal energy produced in the device during an ESD event is generated under the STI layer where it can be more efficiently dissipated towards a substrate.