Ldmos transistor design for providing immunity to cone defects

A method of creating a laterally-diffused metal-oxide semiconductor (LDMOS) transistor, comprising:

• forming a doped body region in a substrate;
• creating a gate electrode above the doped body region;
• forming a high voltage well region in the substrate;
• etching a shallow trench isolation (STI) region within the high voltage well region, the STI region spaced apart from an edge of the high voltage well region by a first distance;
• placing a dielectric material within the STI region;
• covering a portion of the STI region with a cap layer, an edge of the cap layer located a second distance from an edge of the STI region;
• placing a poly gate spanning from the gate electrode to the high voltage well region and extending past the high voltage well region by less than the first distance;
• covering a portion of the cap layer with a field plate;
• and
• spanning the field plate and the poly gate with a metal shield, the metal shield electrically coupling the high voltage well region to the doped body region.

A laterally-diffused metal-oxide semiconductor (LDMOS) transistor made by a process comprising:

• forming a doped body region in a substrate;
• creating a gate electrode above the doped body region;
• forming a high voltage well region in the substrate;
• etching a shallow trench isolation (STI) region within the high voltage well region, the STI region spaced apart from an edge of the high voltage well region by a first distance;
• placing a dielectric material within the STI region;
• covering a portion of the STI region with a cap layer, an edge of the cap layer located a second distance from an edge of the STI region;
• placing a poly gate spanning from the gate electrode to the high voltage well region and extending past the high voltage well region by less than the first distance;
• covering a portion of the cap layer with a field plate;
• and
• spanning the field plate and the poly gate with a metal shield, the metal shield electrically coupling the high voltage well region to the doped body region.