Method of making a floating gate non-volatile MOS semiconductor memory device with improved capacitive coupling and device thus obtained
OwnerGiorgio Servalli, Daniela Brazzelliinventors
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Abstract
A method of making a non-volatile MOS semiconductor memory device includes a formation phase, in a semiconductor material substrate, of isolation regions filled by field oxide and of memory cells separated each other by said isolation regions The memory cells include an electrically active region surmounted by a gate electrode electrically isolated from the semiconductor material substrate by a first dielectric layer; the gate electrode includes a floating gate defined simultaneously to the active electrically region. A formation phase of said floating gate exhibiting a substantially saddle shape including a concavity is proposed.
Claims13
A non-volatile MOS semiconductor memory cell, comprising:
- a substrate of semiconductor material;
- isolation regions formed in said substrate;
- an electrically active region surmounted by a gate electrode, said gate electrode being electrically isolated from said substrate by a first dielectric layer, said gate electrode including a U-shaped floating gate, said U-shaped floating gate comprising a base with a top surface planar with the top surfaces of said isolation regions and comprising a pair of sidewalls that extends vertically above, but not over, the top surfaces of said isolation regions, wherein said U-shaped floating gate includes a base wall and the pair of side walls protruding from said base wall in proximity of said isolation regions, and wherein said base wall has a greater thickness than the thickness of each of said side walls.
A non-volatile MOS semiconductor memory cell, comprising:
- a substrate of semiconductor material;
- isolation regions formed in said substrate;
- an electrically active region surmounted by a gate electrode, said gate electrode being electrically isolated from said substrate by a first dielectric layer, said gate electrode including a U-shaped floating gate, said U-shaped floating gate comprising a base with a top surface planar with the top surfaces of said isolation regions and comprising a pair of sidewalls that extends vertically above, but not over, the top surfaces of said isolation regions, wherein said U-shaped floating gate includes a base wall and the pair of side walls protruding from said base wall in proximity of said isolation regions, and wherein each of said side walls protrudes from said base wall of an equal height of at least 5times the thickness of said base wall.
Dependencies are inferred from the claim text.