Lateral diffusion metal-oxide-semiconductor structure

A LDMOS structure, comprising:

• a source formed in a semiconductor substrate;
• a drain formed in the semiconductor substrate;
• a gate comprising a bottom surface;
• and
• a shallow trench isolation formed in the semiconductor substrate and between the drain and the source, wherein the shallow trench isolation comprises a top surface lower than a top surface of the semiconductor substrate;
• wherein the gate comprises a first portion on the top surface of the shallow trench isolation and a second portion on the top surface of the semiconductor substrate, and wherein the bottom surface of the first portion of the gate is lower than the top surface of the semiconductor substrate.

A LDMOS structure, comprising:

• a source formed in a semiconductor substrate;
• a drain formed in the semiconductor substrate;
• a gate;
• and
• a shallow trench isolation formed in the semiconductor substrate and between the drain and the source, and the shallow trench isolation having a top surface below a top surface of the semiconductor substrate;
• and
• wherein the gate extends over a step between the top surface of the isolation structure and the top surface of the semiconductor substrate.