Semiconductor Device with a Field Ring Edge Termination Structure and a Separation Trench Arranged Between Different Field Rings

A method for producing a semiconductor device, the method comprising:

• providing a semiconductor body comprising a bottom side, a top side opposite the bottom side, and a lateral surface;
• producing an active semiconductor region in the semiconductor body;
• producing an edge region surrounding the active semiconductor region, and such that the edge region comprises a first semiconductor zone having a first conduction type;
• and
• producing at least N field limiting structures in the edge region such that each of the field limiting structures comprises both a field ring and a separation trench formed in the semiconductor body, wherein:
• N≧2;
• each of the field rings has a second conduction type opposite the first conduction type and forms a pn-junction with the first semiconductor zone;
• and
• each of the field rings surrounds the active semiconductor region;
• for each of the field limiting structures, the separation trench of that field limiting structure is arranged between the field ring of that field limiting structure and the active semiconductor region, wherein
• one of the separation trenches is arranged between a first one of the field rings and a second one of the field rings, wherein there is no further field ring arranged between the first one of the field rings and the second one of the field rings;
• the first field ring surrounds the one of the separation trenches and the one of the separation trenches surrounds the second field ring;
• and
• the distance between the one of the separation trenches and the first field ring is less than the distance between the one of the separation trenches and the second field ring.

A semiconductor device, comprising:

• a semiconductor body comprising a bottom side, a top side opposite the bottom side, and a lateral surface;
• an active semiconductor region formed in the semiconductor body;
• an edge region surrounding the active semiconductor region;
• a first semiconductor zone formed in the edge region, the first semiconductor zone having a first conduction type;
• and
• an edge termination structure formed in the edge region and comprising at least N field limiting structures, each of the field limiting structures comprising a field ring, and a separation trench formed in the semiconductor body, wherein:
• N≧1;
• each of the field rings has a second conduction type complementary to the first conduction type and forms a pn-junction with the first semiconductor zone;
• each of the field rings surrounds the active semiconductor region;
• for each of the field limiting structures, the separation trench of that field limiting structure is arranged between the field ring of that field limiting structure and the active semiconductor region, and
• one of the separation trenches is completely filled with a dielectric.