Integrated circuits including vertical diodes. In an example, a first transistor is above a second transistor. The first transistor includes a first semiconductor body extending laterally from a first source or drain region. The first source or drain region includes one of a p-type dopant or an n-type dopant. The second transistor includes a second semiconductor body extending laterally from a second source or drain region. The second source or drain region includes the other of the p-type dopant or the n-type dopant. The first source or drain region and second source or drain region are at least part of a diode structure, which may have a PN junction (e.g., first and second source/drain regions are merged) or a PIN junction (e.g., first and second source/drain regions are separated by an intrinsic semiconductor layer, or a dielectric layer and the first and second semiconductor bodies are part of the junction).