Abstract: The encapsulation of gate stacks of a semiconductor device in an oxide insulative layer and in a silicon nitride etch-stop layer allows the formation of a contact filling for connection to underlying diffusion regions without risk of accidental diffusion contact to gate shorts created by the contact filling. As a result, the gate stacks may be patterned closer together, thus reducing the cell size and increasing the cell density. Furthermore, use of the etch-stop layer makes contact lithography easier since the size of the contact opening can be increased and contact alignment tolerance made less stringent without concern of increasing the cell size or of creating diffusion contact to gate shorts.

Abstract: The encapsulation of gate stacks of a semiconductor device in an oxide insulative layer and in a silicon nitride etch-stop layer allows the formation of a contact filling for connection to underlying diffusion regions without risk of accidental diffusion contact to gate shorts created by the contact filling. As a result, the gate stacks may be patterned closer together, thus reducing the cell size and increasing the cell density. Furthermore, use of the etch-stop layer makes contact lithography easier since the size of the contact opening can be increased and contact alignment tolerance made less stringent without concern of increasing the cell size or of creating diffusion contact to gate shorts.

Abstract: A process for fabricating ultra-high density (e.g., 64Mbit) contactless EPROMs and/or flash EPROMs in a silicon substrate is described. Spaced-apart island members are formed of poly 2/ dielectric/poly 1 layers over gate oxide regions. Each island member is associated with one of the cells within the array, and is separated from each other by trenches extending down to either the field oxide or substrate regions. Elongated, parallel, spaced-apart source/drain regions are formed on adjacent sides of the channel regions by ion implantation. The trenches are then filled with an insulating material and a plurality of wordlines patterned across the array. Each wordline makes electrical contact to the control gate members associated with the single row of cells within the array.