Semiconductor memory device with reduced orientation-dependent oxidation in trench structures
First Claim
1. A deep trench isolation collar oxide layer produced by a process comprising the steps of:
- (a) forming a trench having a sidewall in a substrate;
(b) forming a nitride interface layer over at least a portion of the trench sidewall;
(c) forming an amorphous silicon layer over the nitride interface layer;
(d) forming a nitride-oxynitride barrier layer over the amorphous silicon layer;
(e) etching away a portion of the nitride-oxynitride barrier layer to uncover a portion of the amorphous silicon layer desired to be oxidized for formation of the isolation collar;
(f) oxidizing the amorphous silicon layer to form the isolation collar oxide layer; and
(g) forming a node dielectric layer over the isolation collar oxide layer.
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Accused Products
Abstract
A process for forming an oxide layer on a sidewall of a trench in a substrate. The process comprises the steps of forming the trench in the substrate, forming a nitride interface layer over a portion of the trench sidewall, forming an amorphous layer over the nitride interface layer, and oxidizing the amorphous layer to form the oxide layer. The process may be used, for example, to form a gate oxide for a vertical transistor, or an isolation collar. The invention also comprises a semiconductor memory device comprising a substrate, a trench in the substrate having a sidewall, an isolation collar comprising an isolation collar oxide layer on the trench sidewall in an upper region of the trench, and a vertical gate oxide comprising a gate oxide layer located on the trench sidewall above the isolation collar. The isolation collar oxide layer is disposed over an isolation collar nitride interface layer between the isolation collar oxide layer and the trench sidewall, the gate oxide layer is disposed over a gate nitride interface layer between the gate oxide layer and the trench sidewall, or both.
75 Citations
13 Claims
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1. A deep trench isolation collar oxide layer produced by a process comprising the steps of:
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(a) forming a trench having a sidewall in a substrate;
(b) forming a nitride interface layer over at least a portion of the trench sidewall;
(c) forming an amorphous silicon layer over the nitride interface layer;
(d) forming a nitride-oxynitride barrier layer over the amorphous silicon layer;
(e) etching away a portion of the nitride-oxynitride barrier layer to uncover a portion of the amorphous silicon layer desired to be oxidized for formation of the isolation collar;
(f) oxidizing the amorphous silicon layer to form the isolation collar oxide layer; and
(g) forming a node dielectric layer over the isolation collar oxide layer. - View Dependent Claims (2, 3)
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4. A semiconductor device comprising:
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a substrate having a trench with a sidewall;
an isolation collar including an isolation collar oxide layer on the trench sidewall in an upper region of the trench;
a vertical gate oxide including a gate oxide layer on the trench sidewall in an upper region of the trench above the isolation collar;
at least one of (a) an isolation collar nitride interface layer disposed on the trench sidewall, with the isolation collar disposed over the isolation collar nitride interface layer, and (b) a gate nitride interface layer disposed on the trench sidewall, with the vertical gate oxide disposed over the gate nitride interface layer; and
wherein the trench sidewall, underlying at least one of said isolation collar nitride interface layer and said gate nitride interface layer further includes an oxide layer. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification