Method for fabricating polycrystalline silicon having micro roughness on the surface
AssigneeNEC Corporation
InventorsHirohito Watanabe, Toru Tatsumi
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Abstract
A method for fabricating a polycrystalline silicon having a roughed surface, which is useful for a capacitor electrode is disclosed. The method is featured by depositing a polycrystalline silicon layer in such a manner that grains of silicon are caused at the surface of the polycrystalline silicon layer. The polycrystalline silicon layer thus obtained has a large effective surface area and is suitable for a capacitor electrode because of its increased effective surface area.
Claims20
A method for fabricating a semiconductor device having a memory cell which includes a capacitor, said capacitor having a first electrode, a second electrode and a dielectric layer intervening between said first and second electrodes, said method comprising the steps of:
- depositing an amorphous silicon layer on a substrate;
- performing an annealing process to form a plurality of crystalline nuclei on said amorphous silicon layer and grow said crystalline nuclei to thereby form a plurality of polycrystalline silicon grains, said amorphous silicon layer being thereby converted into a silicon layer having an uneven surface and serving said first electrode of said capacitor;
- forming a dielectric film on the uneven surface of said silicon layer, said dielectric film serving as said dielectric layer of said capacitor;
- and
- forming a conductive layer on said dielectric film, said conductive layer serving as said second electrode of said capacitor.
A method for fabricating a semiconductor device comprising the steps of:
- depositing an amorphous silicon layer on a substrate;
- cleaning said amorphous silicon layer, said amorphous silicon layer thereby having an oxide-free surface;
- annealing said substrate in such a state that said amorphous silicon layer keeps said oxide-free surface, said amorphous silicon layer being thereby converted into a silicon layer having a plurality of silicon grains grown from a surface of said silicon layer, said silicon layer having an uneven surface;
- forming a dielectric layer on the uneven surface of said silicon layer;
- and
- forming a conductive layer on said dielectric layer.
A method for fabricating a semiconductor device comprising the steps of:
- forming an impurity-doped silicon layer on a substrate;
- forming an amorphous silicon layer on said impurity-doped silicon layer;
- annealing said substrate to form a plurality of crystalline nuclei on a surface of said amorphous silicon layer and grow said crystalline nuclei to thereby form a plurality of silicon grains, said amorphous silicon layer being thereby converted into a silicon layer having an uneven surface;
- doping impurities contained in said impurity-doped silicon layer from said impurity-doped silicon layer into said silicon layer having the uneven surface;
- forming a dielectric layer on the uneven surface of said polycrystalline silicon layer;
- and
- forming a conductive layer on said dielectric layer.
A method for fabricating a semiconductor device comprising the steps of:
- forming an impurity-doped silicon layer on a substrate;
- forming a plurality of amorphous silicon projections on said impurity-doped silicon layer;
- annealing said substrate to grow a plurality of polycrystalline silicon grains from a surface of each of said amorphous silicon projections, said amorphous silicon projections being thereby converted respectively into silicon layers each having an uneven surface;
- forming a dielectric film on the uneven surface of each of said silicon layers and on a surface of said impurity-doped silicon layer;
- and
- forming a conductive layer on said dielectric layer.
A method for fabricating a semiconductor device comprising the steps of:
- forming an amorphous silicon layer on a substrate, said amorphous silicon layer having a horizontal portion and a vertical portion projecting from said horizontal portion;
- cleaning said amorphous silicon layer, each of said horizontal portion and said vertical portion of said amorphous silicon layer thereby having an oxide-fee surface;
- annealing said substrate in a condition that each of said horizontal portion and said vertical portion of said amorphous silicon layer keeps said oxide-free surface to thereby form a plurality of crystalline nuclei on each of surfaces of said horizontal portion and said vertical portion of said amorphous silicon layer and grow said crystalline nuclei to form a plurality of silicon grains, said amorphous silicon layer being thereby converted into a silicon layer having an uneven surface;
- forming a dielectric layer on the uneven surface of said silicon layer;
- and
- forming a conductive layer on said dielectric layer.
A method of fabricating a semiconductor capacitor having a first electrode, a second electrode, and a dielectric disposed between said first electrode and said second electrode, comprising the steps of:
- forming said first electrode by depositing an amorphous silicon layer over a substrate and annealing at a temperature above a transition temperature so that a plurality of crystalline nuclei grow to form polycrystalline grains at the surface of said electrode and thereby create a first electrode having an uneven surface;
- forming said dielectric layer on said first electrode with a thickness such that opposing surfaces of said dielectric layer are substantially parallel and substantially replicate said uneven surface of said first electrode;
- forming said second electrode on and conformal to said dielectric layer, whereby capacitance between said first electrode and said second electrode is increased by said uneven surface.
Dependencies are inferred from the claim text.