Method for making a MOSFET with self-aligned source and drain contacts including forming an oxide liner on the gate, forming nitride spacers on the liner, etching the liner, and forming contacts in the gaps

摘要

A method for making a MOSFET in a semiconductor substrate with self aligned source and drain contacts. The method comprises forming a gate oxide layer on the substrate followed by forming a polysilicon gate on the gate oxide layer. A liner oxide layer is formed on the gate and the gate oxide layer and nitride sidewall spacers are formed on the liner oxide layer and adjacent the sidewalls of the gate. A portion of the liner oxide layer and gate oxide layer that lies between the sidewalls of the gate and the nitride sidewall spacers is removed. An oxide layer is then formed around the gate. Next, source and drain regions are formed in the substrate adjacent to the sidewalls of the gate. Finally, a source contact and a drain contact is formed in the area between the gate and the nitride sidewall spacers.