High Voltage Semiconductor Device with Floating Regions for Reducing Electric Field Concentration

A high voltage semiconductor device, comprising:

• a semiconductor substrate;
• a body region of the first conductivity type in the semiconductor substrate;
• a source region of a second conductivity type in the body region;
• a first well region of the second conductivity type in the semiconductor substrate, the first well region laterally extending to contact the body region;
• a drain region of the second conductivity type in the first well region, the drain region being laterally spaced from the source region;
• a second well region of the second conductivity type in the semiconductor substrate, the second well region laterally extending to contact the body region, the first well region having a higher impurity concentration than the second well region;
• and
• floating regions of the first conductivity type embedded in the first and second well regions between the source and drain regions, the floating regions being laterally spaced from one another to thereby form alternating P-N regions along the lateral dimension.

A laterally conducting semiconductor transistor comprising:

• a semiconductor substrate;
• a body region of a first conductivity type in the semiconductor substrate;
• a source region of a second conductivity type in the body region, the source region including an elongated projection with two sides and a rounded tip;
• a first well region of the second conductivity type in the semiconductor substrate, the first well region having a portion extending around the tip of the projection and being in contact with the body region;
• a drain region of the second conductivity type laterally spaced from the source region;
• and
• floating regions of the first conductivity type having portions that are disposed in the first well region between the source and drain regions in the shape of arched stripes extending along the rounded tip of the projection of the source region.