Methods for fabricating integrated circuits with drift regions and replacement gates

A method for manufacturing an integrated circuit comprising:

• providing a semiconductor substrate including a temporary gate structure having a first side and a second side, a first region of a first doping type spaced from the first side of the temporary gate structure, a drift region of the first doping type at least partially positioned between the first region and the first side of the temporary gate structure, a second region of the first doping type proximate the second side of the temporary gate structure, and a third region of an opposite doping type;
• forming a photoresist mask directly on the drift region and the third region by depositing a layer of photoresist over the temporary gate structure, the first region, the second region, the drift region and the third region and etching the layer of photoresist overlying the first region and the second region;
• performing an ion implantation into the first region and the second region, wherein the photoresist mask prevents the drift region and the third region from receiving the ion implantation;
• removing the photoresist mask;
• removing the temporary gate structure and defining a gate trench;
• forming a replacement gate structure in the gate trench;
• depositing an insulating dielectric layer over the replacement gate structure and semiconductor substrate;
• forming trenches in the insulating dielectric layer to expose the first region and the second region;
• and
• siliciding the exposed regions.

A method for manufacturing an integrated circuit comprising:

• providing a semiconductor substrate including a temporary gate structure formed thereon, wherein the temporary gate structure lies over a gate-underlying section of the semiconductor substrate bounded by a first section of the semiconductor substrate and a second section of the semiconductor substrate, wherein the semiconductor substrate includes a first region of a first doping type formed in the first section and spaced from the gate-underlying section, a drift region of the first doping type positioned adjacent the first region and having a first portion formed in the first section and a gate-underlying portion formed in the gate-underlying section, a second region of the first doping type formed in the second section, and a third region of the second doping type including a gate-underlying portion formed in the gate-underlying section and a second portion formed in the second section, wherein the drift region does not extend into the second section and the second region does not extend into the first section;
• simultaneously applying a layer of photoresist over the first region, the first portion of drift region, the second region and the second portion of the third region, and etching the layer of photoresist to form a mask over the first portion of the drift region and the second portion of the third region;
• and
• performing an ion implantation into the first region and the second region;
• unmasking the first portion of the drift region and the second portion of the third region;
• removing the temporary gate structure and defining a gate trench;
• forming a replacement gate structure in the gate trench;
• depositing an insulating dielectric layer over the replacement gate structure and semiconductor substrate;
• forming trenches in the insulating dielectric layer to expose the first region and the second region;
• and
• siliciding the exposed regions.