Semiconductor device having trench charge compensation regions and method

A method for forming a semiconductor device comprising the steps of:

• providing a region of semiconductor material having a first major surface;
• forming a trench in the region of semiconductor material extending from the first major surface;
• forming a plurality of semiconductor layers within the trench including at least two opposite conductivity type semiconductor layers, and at least one buffer layer separating the at least two opposite conductivity type semiconductor layers to form a filled trench compensation region, wherein the buffer layer has a lower dopant concentration less than the at least two opposite conductivity type semiconductor layers at formation;
• forming a control electrode overlying the first major surface and laterally separated from the filled trench compensation region, the control electrode configured to form a channel in the region of semiconductor material during operation;
• forming a first doped region at least partially within the filled trench compensation region configured to electrically couple the channel region to the filled trench compensation region during operation;
• and
• forming a second doped region extending laterally from the trench compensation region into the region of semiconductor material, wherein the second doped region comprises a first conductivity type, and wherein the first doped region comprises a second and opposite conductivity type.

A semiconductor superjunction device comprising:

• a region of semiconductor material having a first major surface;
• a trench compensation region extending into the region of semiconductor material from the first surface including a first layer of a first conductivity type overlying sidewalls and a lower surface of the trench compensation region and a second layer of a second conductivity type overlying the first layer;
• a body region of the first conductivity type formed in the region of semiconductor material adjacent the trench compensation region;
• a source region of the second conductivity type formed in the body region and laterally spaced apart from the trench compensation region so that the source region does not overlie the trench compensation region;
• a gate structure formed overlying the first major surface and interposed between the source region and trench compensation region, wherein the gate structure is laterally spaced apart from the trench compensation region so that a portion of the body region is at the first major surface between the gate structure and trench compensation region, and wherein the gate structure is configured to form a channel in the body region when the device is in operation;
• and
• a first doped region of the second conductivity type formed at least partially within the trench compensation region overlying the first and second layers and configured to electrically couple a drain end of the channel to the second layer when the device is in operation.