A diode structure, formed under a buried dielectric layer of a silicon on insulator (SOI), method of manufacturing the same and design structure thereof are provided. In an embodiment the p-n junction of the diode structure can be advantageously arranged in a vertical orientation. The cathode comprises an N+ epitaxial layer formed upon a P-type substrate. The anode comprises an active region of the P-substrate. Contacts to the cathode and anode are formed through the buried dielectric layer. Contact to the anode is accomplished via a deep trench filled with a conductive plug. The deep trench also provides electrical isolation for the cathode (as well as p-n junction). Advantageously, embodiments of the present invention may be formed during formation of other structures which also include trenches (for example, deep trench capacitors) in order to reduce process steps required to form the diode structure under the buried dielectric layer of the SOI substrate.