Patent ID: 7170103

Claim:
A diode on a silicon wafer, comprising: an active region in a silicon wafer, the active region being heavily doped with a first conductivity type dopant; a first refractory metal silicide layer contacting and covering at least a portion of the active region; an insulation layer contacting and covering at least a portion of the first refractory metal silicide layer, the insulation layer having a diode opening defined by an interior surface extending through the insulation layer and communicating with the first refractory metal silicide layer; a second refractory metal silicide layer lining the interior surface of the diode opening so as to contact the first refractory metal silicide layer; a polysilicon plug within the diode opening, the polysilicon plug being lightly doped with the first conductivity type dopant; a platinum silicide layer contacting the polysilicon plug and separated from the second refractory metal silicide layer; an insulative silicon layer overlying the diode opening, the insulative silicon layer having a passageway extending therethrough and communicating with the platinum silicide layer; and a layer of a material that is capable of changing states and resistivities over the insulative silicon layer, within the passageway, and contacting the platinum silicide layer.