Method of fabricating a lateral semiconductor structure including field plates for self-alignment

A method of fabricating a lateral semiconductor structure comprising the steps of:

• providing a semiconductor substrate;
• forming wells in said substrate;
• forming a dielectric layer on said substrate;
• forming field region openings in said dielectric layer;
• forming field regions in said substrate through said field region openings;
• forming field oxidation regions on said substrate above said field regions, the formation of said field oxidation regions being self-aligned to said field region openings;
• forming field plates at least partially on said field oxidation regions;
• forming a first active device region in said substrate, the formation of which is self-aligned to said field plates;
• and
• forming a second active device region in said first active device region, the formation of which is also self-aligned to said field plates.

A method of fabricating a lateral semiconductor structure comprising the steps of:

• providing a semiconductor substrate having a buried layer therein;
• isolating a device area in said substrate;
• forming a sinker in said device area, said sinker extending to said buried layer;
• forming wells in said device area;
• forming a first dielectric layer on said substrate;
• forming field region openings in said first dielectric layer;
• forming field regions in said device area through said field region openings;
• forming field oxidation regions on said device area above said field regions, the formation of said field oxidation regions being self-aligned to said field region openings;
• forming polysilicon field plates at least partially on said field oxidation regions;
• forming a first active device region in said device area, the formation of which is self-aligned to said field plates;
• forming a second active device region in said first active device region, the formation of which is also self-aligned to said field plates;
• forming a second dielectric layer on said structure;
• and
• forming contacts to the active device regions.