Titanium semiconductor bridge igniter

Abstract

A titanium semiconductor bridge igniter ( 10, 10 ′) has a substrate ( 12, 12 ′) on which is carried a pair of spaced-apart pads ( 18 a , 18 b ) connected by a bridge ( 20 ). The pads ( 18 a , 18 b ) and bridge ( 20 ) are made of a layer of polysilicon ( 22 ) or crystalline silicon ( 22 ′) covered by a layer of titanium ( 24 ). Metal lands ( 26 a , 26 b ) overlie the pads ( 18 a , 18 b ) but leave the bridge ( 20 ) exposed so that it can be placed in contact with an energetic material charge ( 42 ). A method of stabilizing the titanium semiconductor bridge igniter ( 10, 10 ′) against temperature-induced variations in electrical resistance of bridge ( 20 ) includes heating the titanium semiconductor bridge igniter ( 10, 10 ′) to an elevated temperature, e.g., from about 37° C. to about 250° C.

1 . A semiconductor bridge igniter comprising: 
 a substrate;    an electrical bridge structure disposed on the substrate, the bridge structure comprising a bridge section and pad sections, the bridge section extending between and connecting the pad sections, the pad sections each comprising a layer of semiconductor material on the substrate and a layer of titanium disposed on the semiconductor material, and the bridge section consisting of a layer of semiconductor material and a layer of titanium disposed on the semiconductor material; and    a pair of electrically conductive lands each overlying a respective one of the pad sections and being spaced apart from each other to leave the bridge section exposed.    
   
   
       2 . The igniter of  claim 1  wherein the igniter has a lower input energy requirement for initiation than an identically sized semiconductor bridge igniter layer that comprises a bridge section that includes a layer of tungsten.  
   
   
       3 . A semiconductor bridge igniter comprising: 
 a substrate;    an electrical bridge structure disposed on the substrate, the bridge structure comprising a bridge section and pad sections, the bridge section extending between and connecting the pad sections, the pad sections and bridge section each comprising a layer of semiconductor material on the substrate and a layer of metal disposed on the semiconductor material, the layer of metal consisting of titanium and the bridge section being free of a layer of tungsten; and    a pair of electrically conductive lands each overlying a respective one of the pad sections and being spaced apart from each other to leave the bridge section exposed.    
   
   
       4 . The igniter of  claim 1  wherein the pad sections each consist of a layer of semiconductor material.  
   
   
       5 . The semiconductor bridge igniter of any one of claims  1 ,  2 ,  3  or  4  further comprising a pair of electrical leads, one connected to a respective one of the electrically conductive lands.