Wide-Bandgap Semiconductor Device with Trench Gate Structures

Abstract

A semiconductor device includes trench gate structures extending from a first surface into a semiconductor body from a wide-bandgap semiconductor material. The trench gate structures separate mesa portions of the semiconductor body from each other. In the mesa portions, body regions form first pn junctions with a drain structure and directly adjoin first mesa sidewalls. Source regions in the mesa portions form second pn junctions with the body regions, wherein the body regions separate the source regions from the drain structure. The source regions directly adjoin the first mesa sidewalls and second mesa sidewalls opposite to the first mesa sidewalls.

1 . A semiconductor device, comprising:
 trench gate structures extending from a first surface into a semiconductor body formed from a wide-bandgap semiconductor material and separating mesa portions of the semiconductor body from each other;   body regions in the mesa portions, wherein the body regions form first pn junctions with a drain structure and directly adjoin first mesa sidewalls;   diode regions between the body regions and the trench gate structures and directly adjoining second mesa sidewalls, wherein a mean net dopant concentration in the diode regions is higher than in the body regions; and   source regions in the mesa portions, the source regions forming second pn junctions with the body regions, the body regions separating the source regions from the drain structure, wherein the source regions directly adjoin the first mesa sidewalls and second mesa sidewalls opposite to the first mesa sidewalls.   
     
     
         2 . The semiconductor device of  claim 1 , wherein
 the source regions comprise first sections directly adjoining the first mesa sidewalls and one or more second sections directly adjoining the second mesa sidewalls.   
     
     
         3 . The semiconductor device of  claim 2 , wherein
 the one or more second sections are separated from each other along longitudinal axes of the mesa portions.   
     
     
         4 . The semiconductor device of  claim 2 , wherein
 the one or more second sections comprise a continuous structure extending along the complete longitudinal axis of the mesa portion.   
     
     
         5 . The semiconductor device of  claim 2 , wherein
 the source regions further comprise connection sections sandwiched between and directly adjoining the first and second sections, wherein the connection sections are separated from each other along longitudinal axes of the mesa portions.   
     
     
         6 . The semiconductor device of  claim 5 , wherein
 the connection sections are separated from each other along the longitudinal axes of the mesa portions by a separation region of a conductivity type of the body region.   
     
     
         7 . The semiconductor device of  claim 5 , wherein
 the source regions have a ladder shape having rails and rungs, with the first and second sections forming the rails and the connection sections forming the rungs.   
     
     
         8 . The semiconductor device of  claim 5 , wherein
 a first horizontal extension of the connection sections along the longitudinal axes of the mesa portions is smaller than a distance between neighboring connections sections along the longitudinal axes of the mesa portions.   
     
     
         9 . The semiconductor device of  claim 5 , wherein
 a first horizontal extension of the connection sections along the longitudinal axes of the mesa portions is at least 200 nm and at most 5 μm.   
     
     
         10 . The semiconductor device of  claim 2 , wherein
 a vertical extension of the one or more second sections orthogonal to the first surface is equal to a vertical extension of the first sections orthogonal to the first surface.   
     
     
         11 . The semiconductor device of  claim 2 , wherein a vertical extension of the one or more second sections orthogonal to the first surface is greater than a vertical extension of the first sections orthogonal to the first surface. 
     
     
         12 . The semiconductor device of  claim 2 , wherein
 a vertical extension of the one or more second sections orthogonal to the first surface is at least 200 nm and at most 1 μm.   
     
     
         13 . The semiconductor device of  claim 5 , wherein
 the connection sections are separated from each other along the longitudinal axes of the mesa portions by surface sections of diode regions, the diode regions extending from the first surface into the semiconductor body and forming diode junctions with the drain structure, wherein a vertical extension of the diode regions is greater than a vertical extension of the trench gate structures.   
     
     
         14 . The semiconductor device of  claim 1 , further comprising:
 trench source structures extending from the first surface into the semiconductor body, the trench source structures comprising trench source electrodes electrically connected to a first load electrode.   
     
     
         15 . The semiconductor device of  claim 14 , wherein
 corresponding dimensions of the trench gate structures and the trench source structures are equal.   
     
     
         16 . The semiconductor device of  claim 14 , wherein
 at least nine trench gate structures are formed between two neighboring ones of the trench source structures.   
     
     
         17 . The semiconductor device of  claim 1 , wherein
 the wide-bandgap semiconductor material has a hexagonal crystal structure.   
     
     
         18 . A semiconductor device, comprising:
 trench gate structures extending from a first surface into a semiconductor body and separating mesa portions of the semiconductor body from each other;   body regions in the mesa portions, wherein the body regions form first pn junctions with a drain structure and directly adjoin first mesa sidewalls;   diode regions between the body regions and the trench gate structures and directly adjoining second mesa sidewalls, wherein a mean net dopant concentration in the diode regions is higher than in the body regions;   source regions forming second pn junctions with body regions, wherein the body regions separate the source regions from the drain structure; and   trench source structures extending from the first surface into the semiconductor body, the trench source structures comprising trench source electrodes electrically connected to a first load electrode.   
     
     
         19 . The semiconductor device of  claim 1 , wherein portions of the diode regions are formed in a vertical projection of the trench gate structures.