Patent ID: 8143160
Filing Date: 2012-03-27
Classification: H01L

Abstract:
1. A method of forming a contact plug of a semiconductor device, the method comprising: forming select lines and word lines over a semiconductor substrate; forming junctions in the semiconductor substrate exposed between the select lines and between the word lines; forming a nitride layer along sidewalls of the select lines and the semiconductor substrate between the select lines; forming an insulating layer over the nitride layer to fill a region between the select lines; etching the insulating layer to expose the nitride layer between the select lines thereby forming a contact hole; forming a high-k layer along the insulating layer including the contact hole, wherein an etch selectivity of the high-k layer is different from that of the nitride layer; performing an anisotropic etch process to selectively etch the high-k layer such that the high-k layer remains on sidewalls of the contact hole, wherein the nitride layer between the select lines and a top surface of the insulating layer are exposed; removing the nitride layer between the select lines to expose the junction between the select lines under a condition that the nitride layer on the sidewalls of the select lines is protected by the high-k layer on the sidewalls of the contact hole; removing the high-k layer on the sidewalls of the contact hole to expose sidewalls of the insulating layer through the contact hole; and forming conductive material within the contact hole, thereby forming a contact plug connected to the junction between the select lines in the contact hole.