1. A method of forming a planar diode comprising:
providing a substrate of a first conductivity type;
depositing a layer of oxide over the substrate;
using a mask to expose the central portion of the oxide layer for etching;
removing the central portion of the oxide via etching;
diffusing dopants into the substrate via window diffusion to form a single region having a uniform second conductivity type;
plating a metal onto the window and on the opposite side of the substrate, wherein the oxide acts as a mask for the plating of the metal, and the metal is plated only onto the window and is not plated onto the oxide; and
coating the remaining oxide and a portion of the plating on a side of the substrate with a passivating agent,
wherein the planar diode is formed using only one mask.