Method to manufacture short channel trench MOSFET

摘要

Aspects of the present disclosure describe a trench MOSFET with a channel length that may be controlled by counterdoping the body-drain junction to form a straggle region adjacent to the trenches. The channel length is defined between the straggle region at the bottom and a source region at the top. Both of the straggle region and the source region are of the same conductivity type though they may be different ion species. It is emphasized that this abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

主权项

1. A method for forming a trench MOSFET, comprising:
forming one or more trenches extending vertically into a substrate of a first conductivity type semiconductor material, wherein each of the one or more trenches is provided with a gate insulator on each sidewall and filled with a conductive material with the gate insulator between the conductive material and the sidewalls of the one or more trenches; forming a body region of a second conductivity type between two neighboring trenches at an upper portion of the trenches; forming a straggle region of the first conductivity type adjacent to the sidewalls of the one or more trenches, the straggle region counter-dopes the body region to form a junction between the body and the drain at the sidewalls of the trenches, wherein a depth of the junction at a location adjacent to the sidewalls of the one or more trenches is shallower in depth compared to that of the junction at a location between two adjacent trenches; and forming a source region of the first conductivity type above the body region, wherein a channel of the MOSFET is defined by the straggle region and the source region.