Manufacturable single-chip hydrogen sensor

Abstract

A robust single-chip hydrogen sensor and a method for fabricating such a sensor. By utilizing an interconnect metallization material that is the same or similar to the material used to sense hydrogen, or that is capable of withstanding an etchant used to pattern a hydrogen sensing portion, device yields are improved over prior techniques.

1 . A method for fabricating a silicon-based hydrogen sensor, comprising providing an interconnect metallization and a hydrogen sensing portion, wherein the interconnect metallization and the hydrogen sensing portion are both composed of a first material.  
   
   
       2 . The method of  claim 1 , wherein the first material is a palladium nickel alloy.  
   
   
       3 . The method of  claim 1 , further comprising covering the interconnect metallization with a material selected from the group consisting of an oxide and a nitride.  
   
   
       4 . The method of  claim 1 , wherein the silicon-based hydrogen sensor is a single chip sensor comprising a bulk silicon substrate, temperature control means, at least one sense transistor, and at least one sense resistor.  
   
   
       5 . The method of  claim 1 , further comprising providing a silicided contact between the interconnect metallization and an underlying base portion.  
   
   
       6 . The method of  claim 5 , wherein providing a silicided contact comprises: 
 masking the underlying base portion;    etching a contact portion through the masked underlying base portion;    depositing a contact material;    sintering the contact material; and    removing any unreacted contact material.    
   
   
       7 . The method of  claim 6 , wherein the contact material is selected from the group consisting of cobalt, titanium, tungsten, platinum, tantalum, and molybdenum.