IGBT Having an Emitter Region with First and Second Doping Regions

Abstract

An IGBT includes a semiconductor substrate, a source metallization and an emitter metallization. The semiconductor substrate includes a source region of a first conductivity type, a body region of a second conductivity type, a drift region of the first conductivity type, and an emitter region of the second conductivity type. The source metallization is in contact with the source region. The emitter metallization is in contact with the emitter region. The emitter region includes a first doping region of the second conductivity type forming an ohmic contact with the emitter metallization and a second doping region of the second conductivity type forming a non-ohmic contact with the emitter metallization.

1 - 23 . (canceled) 
     
     
         24 . An IGBT, comprising:
 a semiconductor substrate comprising a source region of a first conductivity type, a body region of a second conductivity type, a drift region of the first conductivity type and an emitter region of the second conductivity type;   a source metallization in contact with the source region;   an emitter metallization in contact with the emitter region, the emitter region comprising a first doping region of the second conductivity type forming an ohmic contact with the emitter metallization and a second doping region of the second conductivity type forming a non-ohmic contact with the emitter metallization.   
     
     
         25 - 30 . (canceled) 
     
     
         31 . The IGBT of  claim 24 , wherein the non-ohmic contact is a Schottky contact. 
     
     
         32 . The IGBT of  claim 24 , wherein the first doping region has a higher surface doping concentration than the second doping region. 
     
     
         33 . The IGBT of  claim 32 , wherein the first doping region has a surface doping concentration of at least 10 19 /cm 3 . 
     
     
         34 . The IGBT of  claim 32 , wherein the second doping region has a surface doping concentration of less than 10 19 /cm 3 . 
     
     
         35 . The IGBT of  claim 24 , wherein the first doping region comprises first dopants of a first doping type and the second doping region comprises second dopants of the first doping type, wherein the second dopants are different than the first dopants. 
     
     
         36 . The IGBT of  claim 35 , wherein the second dopants are selected from the group consisting of selenium, sulphur, titanium, and bismuth. 
     
     
         37 . The IGBT of  claim 24 , wherein the drift region has a doping concentration lower than the doping concentration of the first doping region of the emitter region and is at least in direct contact with the first doping region of the emitter region. 
     
     
         38 . The IGBT of  claim 24 , further comprising a field stop region of the first conductivity between the drift region and the emitter region, the field stop region having a doping concentration higher than the drift region and lower than the first doping region of the emitter region, the field stop region being at least in direct contact with the first doping region of the emitter region. 
     
     
         39 . The IGBT of  claim 24 , further comprising a plurality of spaced apart first doping regions. 
     
     
         40 . The IGBT of  claim 24 , further comprising a plurality of spaced apart second doping regions. 
     
     
         41 . The IGBT of  claim 24 , wherein the second doping region is formed by portions of the drift region. 
     
     
         42 . The IGBT of  claim 24 , further comprising a field stop region of the first conductivity type between the drift region and the emitter region, the field stop region having a doping concentration higher than the doping concentration of the drift region and lower than the doping concentration of the first doping region of the emitter region, wherein the second doping region is formed by portions of the field stop region.