Junction barrier schottky rectifiers having epitaxially grown p+-n junctions and methods of making

Abstract

A junction barrier Schottky (JBS) rectifier device and a method of making the device are described. The device comprises an epitaxially grown first n-type drift layer and p-type regions forming p + -n junctions and self-planarizing epitaxially over-grown second n-type drift regions between and, optionally, on top of the p-type regions. The device may include an edge termination structure such as an exposed or buried P + guard ring, a regrown or implanted junction termination extension (JTE) region, or a “deep” mesa etched down to the substrate. The Schottky contact to the second n-type drift region and the ohmic contact to the p-type region together serve as an anode. The cathode can be formed by ohmic contact to the n-type region on the backside of the wafer. The devices can be used in monolithic digital, analog, and microwave integrated circuits.

1 - 50 . (canceled) 
     
     
         51 . A semiconductor device comprising:
 a semiconductor substrate of a first conductivity type;   a semiconductor drift layer above the substrate;   a plurality of highly doped epitaxial layer regions of semiconductor material of a second conductivity type different than the first conductivity type, each of the highly doped epitaxial layer regions separated from one another on the drift layer to form a plurality of junction barriers therewith, the highly doped epitaxial layer regions each having an upper surface and sidewalls; and   a plurality of epitaxial drift layer regions of semiconductor material of the first conductivity type, at least some of the epitaxial drift layer regions being disposed between sidewalls of adjacent of the highly doped epitaxial layer regions to electrically couple with the drift layer;   at least one ohmic contact with at least some of the plurality of highly doped epitaxial layer regions; and   at least one Schottky contact with at least some of the drift layer regions of semiconductor material.   
     
     
         52 . The semiconductor device of  claim 51 , wherein each of the highly doped epitaxial layer regions is an elongate finger. 
     
     
         53 . The semiconductor device of  claim 51 , wherein the plurality of epitaxial drift layer regions of the first conductivity type extend above and over the upper surfaces of the plurality of highly doped epitaxial layer regions of the second conductivity type to contact one another. 
     
     
         54 . The semiconductor device of  claim 51 , wherein the device comprises a semiconductor buffer layer of the first semiconductor type on the substrate, wherein the semiconductor drift layer is on the semiconductor buffer layer. 
     
     
         55 . The semiconductor device of  claim 51 , wherein the semiconductor substrate, the semiconductor drift layer, the highly doped epitaxial layer regions, and the epitaxial drift layer regions are silicon carbide. 
     
     
         56 . The semiconductor device of  claim 51 , wherein the at least one ohmic contact and the at least one Schottky contact are both formed by a single metal layer. 
     
     
         57 . The semiconductor device of  claim 51 , wherein the drift layer and the epitaxial drift layer regions each have a dopant concentration of 1×10 14 /cm 3  to 1×10 17 /cm 3 . 
     
     
         58 . The semiconductor device of  claim 51 , wherein the epitaxial drift layer regions have a different dopant concentration than the semiconductor drift layer. 
     
     
         59 . The semiconductor device of  claim 51 , further comprising an ohmic contact on the semiconductor substrate opposite the highly doped epitaxial layer regions and the epitaxial drift layer regions. 
     
     
         60 . The semiconductor device of  claim 51 , further comprising a highly doped epitaxial bus-bar of the second conductivity type connecting the highly doped epitaxial layer regions. 
     
     
         61 . The semiconductor device of  claim 60 , wherein:
 the bus-bar has a first width;   each of the highly doped epitaxial layer regions is an elongate finger having a second width; and   the second width is less than the first width.   
     
     
         62 . The semiconductor device of  claim 51 , wherein the at least one ohmic contact has a different composition than the at least one Schottky contact. 
     
     
         63 . The semiconductor device of  claim 51 , further comprising an edge termination structure in a peripheral portion of the device. 
     
     
         64 . A pinch diode made of a high bandgap semiconductor, the diode comprising:
 a substrate of the high bandgap semiconductor of a first conductivity type;   a plurality of highly doped epitaxial layer regions of the high bandgap semiconductor of a second conductivity type different than the first conductivity type, each of the highly doped epitaxial layer regions separated from one another to form a plurality of junction barriers with underlying of the high bandgap semiconductor material; and   a plurality of epitaxial drift layer regions of the high bandgap semiconductor of the first conductivity type, at least some of the epitaxial drift layer regions being disposed between adjacent of the highly doped epitaxial layer regions to form a junction barriers with the highly doped epitaxial layer regions;   at least one ohmic contact with at least some of the plurality of highly doped epitaxial layer regions; and   at least one Schottky contact with at least some of the drift layer regions of semiconductor material.   
     
     
         65 . The pinch diode of  claim 64 , wherein the high bandgap semiconductor is silicon carbide. 
     
     
         66 . The pinch diode of  claim 64 , wherein the plurality of epitaxial drift layer regions of the first conductivity type extend above and over the upper surfaces of the plurality of highly doped epitaxial layer regions of the second conductivity type to contact one another. 
     
     
         67 . The pinch diode of  claim 64 , wherein the at least one ohmic contact and the at least one Schottky contact are both formed by a single metal layer.