Self-Aligned, Borderless Contact With Nitride Layer
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
The deposition of an intermediate nitride layer permits construction of self-aligned, borderless contacts to diffused regions of metal oxide devices, thus decreasing processing time and effecting a barrier to possible impurity diffusion. Wafer processing for contact holes of both the self-aligned (no spacing between polysilicon and contact hole) and borderless (no spacing between the recessed oxide and contact hole) types are illustrated in Figs. 1a and 2a and Figs. 1b and 2b, respectively. For self-aligned contacts, wafer 1 is initially coated with polysilicon layer 2 and chemical vapor deposited (CVD) oxide layer 3, lithographically defined and etched. Another layer of CVD oxide is deposited and etched to produce sidewalls 4. For the borderless contacts, recessed oxide areas 5 are formed on the wafer 1.