Method of manufacturing a mosfet structure

A method of forming a lateral MOSFET in an integrated circuit, the method comprising:

• forming a drain contact of a second conductivity type with a high density dopant in a substrate adjacent a surface of the substrate;
• forming a top gate of a first conductivity type in the substrate adjacent the surface of the substrate and a predetermined distance from the drain contact after the drain contact is formed;
• and
• wherein the drain contact is formed to extend deeper from the surface of the substrate than the top gate and is formed to have a higher dopant density at every depth than the top gate so a mask is not needed to shield the drain contact from the first conductivity dopants during formation of the top gate.

A method of forming a high voltage bipolar transistor in an integrated circuit, the method comprising:

• forming a first region of relatively thick material on a surface of a substrate;
• forming a second region of relatively thick material on the surface of the substrate a predefined distance from the first region;
• introducing dopant of a second conductivity type to form a base region in the substrate using first edges of the first and second regions to form edges of the base region, wherein the base region is positioned between the first and second regions;
• introducing dopants of a first conductivity type to form a first top gate using a second edge of the first region as a mask to form an edge of the first top gate, wherein the distance between the first top gate and the base region is defined by the lateral length of the first region;
• and
• introducing dopants of the first conductivity type to form a second top gate using a second edge of the second region as a mask to form an edge of the second top gate, wherein the distance between the second top gate and the base region is defined by the lateral length of the second region.