Semiconductor devices including a diode and a resistor are disclosed herein. An example of a semiconductor device includes a substrate having a surface. A first doped semiconductive region is disposed in the substrate below the surface. A second doped semiconductive region is disposed in the substrate and extends between the surface and the first doped semiconductive region. The second doped semiconductive region is at least partially in contact with the first doped semiconductive region. The first doped semiconductive region and the second doped semiconductive region together define an isolation tank. A third doped semiconductive region is disposed in the isolation tank and is in contact with the surface. The second doped semiconductive region and the third doped semiconductive region form a diode. At least one opening in the isolation tank forms a resistive path for current to flow between the substrate and the third doped semiconductive region.