Methods and Apparatus for ESD Structures

A method comprising:

• forming an ESD cell in a first active area, the first active area being in a well of a first conductivity type disposed in a semiconductor substrate;
• forming a first isolation ring around the first active area;
• forming a second isolation ring around the first active area;
• forming a second active area surrounding the first isolation ring, the second active area comprising a first highly-doped region of the first conductivity type;
• and
• forming a reverse biased diode in a third active area, the third active area surrounding the first active area and separated from the second active area by the second isolation ring, the reverse biased diode comprising a first lightly-doped region of the first conductivity type and a second highly-doped region of a second conductivity type, the first lightly-doped region having a higher dopant concentration than the well.

A method comprising:

• forming a first isolation ring surrounding a first active area;
• forming a second isolation ring surrounding the first isolation ring, the second isolation ring separating a second active area and a third active area;
• forming an ESD cell in the first active area, the ESD cell being coupled to a first terminal and a second terminal, the first terminal being a voltage supply terminal;
• forming a reverse-biased diode in the second active area with respect to the first terminal;
• and
• forming a body contact in the third active area.