Fabrication of a Small, Self-Aligned, Shallow Implanted Guard Ring for Schottky Diodes
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
A method has been developed for forming narrow guard rings around Schottky barrier diodes (SBDs). An annular guard ring is defined by a sidewall technique over a P-type implanted region. Etching leaves only the protected part of the P-N junction under the sidewall with the SBD then formed in the etched region within the guard ring. (Image Omitted) The guard rings on SBDs are used to reduce failures which may occur due to effects at the perimeter of the contact opening. In some cases the density and performance of a semiconductor chip may degrade due to increased area and capacitance associated with the wide P+ guard ring (Fig. 1) used in conventional processes. The structure shown includes an oxide layer 2, a nitride layer 3, a PtSi layer 4 in the annulus, recessed oxide isolation (ROI) 5 and N- Si 6.