Structure for an LDMOS transistor and fabrication method thereof

A structure for an LDMOS transistor, comprising:

• a semiconductor silicon substrate having a surface region of a first conductive type;
• a horseshoe-shaped gate layer formed on the semiconductor silicon substrate, in which the gate layer comprises a transverse-extending area, a first lengthwise-extending area connected to a left end of the transverse-extending area and a second lengthwise-extending area connected to a right end of the transverse-extending area;
• a first source region of the first conductive type formed in the surface region of the semiconductor silicon substrate and disposed at the left periphery of the first lengthwise-extending area of the gate layer;
• a second source region of the first conductive type formed in the surface region of the semiconductor silicon substrate and disposed at the right periphery of the second lengthwise-extending area of the gate layer;
• a first drain region of the first conductive type formed in the surface region of the semiconductor silicon substrate and disposed between the first lengthwise-extending area and the second lengthwise-extending area of the gate layer;
• a first ion-diffusion body of a second conductive type formed in the surface region of the semiconductor silicon substrate and surrounding the sidewalls and bottom of the first source region;
• and
• a second ion-diffusion body of a second conductive type formed in the surface region of the semiconductor silicon substrate and surrounding the sidewalls and bottom of the second source region;
• wherein, the left periphery of the first lengthwise-extending area of the gate layer overlaps the periphery of the first ion-diffusion body to form a first overlapping portion, and the right periphery of the second lengthwise-extending area of the gate layer overlaps the periphery of the second ion-diffusion body to form a second overlapping portion.