The present disclosure relates to a secure device having a physical unclonable function and methods of manufacturing such a secure device. The device includes a substrate and at least one high-k/metal gate device formed on the substrate. The at least one high-k/metal gate device represents the physical unclonable function. In some cases, the at least one high-k/metal gate device may be subjected a variability enhancement. In some cases, the secure device may include a measurement circuit for measuring a property of the at least one high-k/metal gate device.