Patent ID: 6753569
Filing Date: 2004-06-22
Classification: H01L

Abstract:
A split-gate flash memory cell structure having a trench isolation devoid of the â€œsmilingâ€  effect comprising:a substrate; a first oxide layer atop said substrate serving an a gate oxide; a floating gate atop said first oxide layer; a trench formed as a single continuous opening through said floating gate and said first oxide layer and into said substrate, wherein said single continuous opened surfaces of said floating gate, said first oxide layer and said substrate form interior trench walls; a first conformal layer lining said interior trench walls, said first conformal layer being in contact with and extending over said continuous surfaces of said flouting gate, said first oxide and said substrate, said first conformal layer comprises oxide; a second conformal layer lining said interior trench walls, said second conformal layer being in contact with said first conformal layer and extending over said continuous surfaces of said floating gate, said first oxide and said substrate, said second conformal layer comprises nitride; an isolation oxide tilling said trench, wherein said isolation oxide is devoid of said â€œsmilingâ€  effect in proximity to said floating gate; a second oxide layer atop said floating gate; a third oxide layer atop said isolation oxide filling said trench and atop said second oxide layer atop said floating gate; a control gate atop said third oxide layer.