N.A.H. Wils

A 25 mu m/sup 2/ bulk full CMOS SRAM cell technology with fully overlapping contacts

The authors describe a 25.2 mu m/sup 2/ bulk full CMOS SRAM cell for application in high-density static memories fabricated in a 14-mask process using minimum dimensions of 0.5 mu m at a comparatively relaxed 1.2 mu m pitch. A very aggressive n/sup +//p/sup +/ spacing and a fully overlapping contact technology are the key elements used to achieve a competitive cell area. The functionality of the cell was shown on a 1 kb test memory.<<ETX>>

Compact poly-CMP embedded flash memory

Abstract In this paper, the compact poly-CMP cell concept is presented as a good candidate for scaled embedded flash memory in future mainstream CMOS technologies. In this compact cell concept the access gate is placed next to the stacked gate transistor. The access gate has a flat top surface due to the use of chemical mechanical polishing (CMP) and therefore no depth of focus problems with the exposure of the access gate mask occur. The feasibility is proven by electrical results on mini arrays in 0.25-μm CMOS technology. Both Fowler–Nordheim tunneling and source side injection programming is possible. The program and erase degradation is investigated by endurance cycling.

Geometry Dependent Bird's Beak Formation for Submicron LOCOS Isolation

Birds beak formation is one of the major problems for LOCOS field isolation. In this paper we demonstrate that the birds beak length is not a constant, but depends strongly on geometry of the oxidatioin mask for submicron mask dimensions. The birds beak length can vary up to a factor of 4, dependent on mask geometry. Four independent geometry effects are distinguished and their impact on an IC-process is discussed.