Integrated circuits, methods of forming integrated circuits, and methods of determining gate dielectric layer electrical thickness in integrated circuits are provided. An exemplary integrated circuit includes a semiconductor substrate including an active region and an STI structure disposed therein, adjacent to the active region. A first gate electrode structure overlies the active region and includes a first gate dielectric layer and a first gate electrode layer. A second gate electrode structure includes a second gate dielectric layer that overlies the first gate electrode layer and a second gate electrode layer that overlies the second gate dielectric layer. A source and drain region are formed in the active region, adjacent to the first gate electrode structure. First electrical interconnects are in electrical communication with the source and drain regions. A second electrical interconnect is in electrical communication with the first gate electrode layer.