Method of forming a semiconductor structure to provide electrostatic discharge protection

Abstract

An improved method is disclosed for protecting active and passive devices against electrostatic discharge (ESD). The method forms a device which is an improved semiconductor diode having anode, injector and ohmic contact regions located within a cathode region. The improved semiconductor diode allows for ESD higher currents without damage to active or passive devices including, for example, resistor-capacitor networks or resistor-capacitor-inductor networks incorporating the improved semiconductor diode.

What is claimed is:  
     
         1 . A method for forming a semiconductor diode for protection against electrostatic discharge comprising the steps of: 
 forming an N type semiconductor substrate;    forming a P well cathode within the N type semiconductor substrate;    forming an N+ type anode region within the P well cathode;    forming an N+ type injector region within the P well cathode and spaced apart from the N+ type anode region;    forming a P+ type ohmic contact region within the P well cathode, the N+ type injector region and the P+ type ohmic contact region are adjacent and co-planar to each other;    forming a first metal electrode electrically connected to the N+ type anode region; and    forming a second metal electrode in electrical contact with both the N+ type injector region and the P+ type ohmic contact region.    
     
     
         2 . The method in accordance with    claim 1    wherein the semiconductor diode is fabricated as part of a monolithic integrated circuit.  
     
     
         3 . The method in accordance with    claim 1    wherein the first metal electrode and the second metal electrode comprise aluminum.  
     
     
         4 . The method in accordance with    claim 1    wherein the N+ type injector region begins to introduce minority carriers when the breakdown current increases.  
     
     
         5 . The method in accordance with    claim 4    wherein the introduction of minority carriers from the N+ type injector region increases conductivity of the semiconductor diode.  
     
     
         6 . The method in accordance with    claim 5    wherein a maximum current that the semiconductor diode can carry without realizing damage thereto is increased with the increase in the conductivity of the semiconductor diode.  
     
     
         7 . The method in accordance with    claim 6    wherein the maximum current that the semiconductor diode can carry without realizing damage thereto protects against electrostatic discharge damage.  
     
     
         8 . A method for forming a semiconductor diode for protection against electrostatic discharge comprising, in combination: 
 forming a semiconductor substrate of one type conductivity;    forming a region of opposite type conductivity located within the semiconductor substrate;    forming a first region of said one type conductivity and having a higher concentration of impurities than the concentration of impurities in the semiconductor substrate located within the region of opposite type conductivity;    forming an injector region of said one type conductivity and having a higher concentration of impurities than the concentration of impurities in the semiconductor substrate located within the region of opposite type conductivity and spaced apart from the first region;    forming an ohmic contact region located within the region of opposite type conductivity, the injector region and the ohmic contact region are adjacent and co-planar to each other;    forming a first metal electrode electrically connected to the first region; and    forming a second metal electrode in electrical contact with both the injector region and the ohmic contact region.