Method for Reducing Channel Encroachment Through Field Doping
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
A method is disclosed for making active channel and field regions in a way that the field region dopant is prevented from encroaching into the active channel region and creating parasitic components in the structure. This is accomplished by using a multilayer resist film, applied at the ROX (recessed oxide) definition mask where the top layer is used as the photo-imaging layer for the doped field regions. An underlying resist layer is exposed and developed in such a way that it is pulled back to the desired position of the active channel region. The amount by which this layer is pulled back is determined by the desired separation between the active channel region and the field region. The method includes the following steps described with reference to Figs. 1-3. 1.