N Skin Elimination in UMOS Device by Reoxidation
Original Publication Date: 1980-Jan-01
Included in the Prior Art Database: 2005-Feb-13
Fig. 1 shows a partially fabricated UMOS (U-grooved metal oxide semiconductor) dynamic memory cell 5 isolated from other areas by dielectric isolation 6. During the formation of the N+ ion implant 7 of the UMOS dynamic memory cell 5, the sidewalls 8 will receive a partial dose due to the substrate 7 degree angle (tilt in ion implanter) and the ion beam divergence, including other non-perpendicularities, causing the formation of an N+ skin on sidewalls 8. This skin will prevent operation of the device.