US5691249A — Method for fabricating polycrystalline silicon ha…

Claim 1

Independent Claim 145 words

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.

Claim 2

Independent Claim 145 words

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.

Claim 3

Dependent Claim 38 words

The method as claimed in claim 1, wherein said step of performing an annealing process is carried out at a temperature that is higher than a transition temperature from an amorphous phase to a polycrystalline phase of silicon.

Claim 4

Dependent Claim 30 words

The method as claimed in claim 1, wherein said step of performing an annealing process is carried out at a temperature in a range between 580° C. and 750° C.

Claim 5

Independent Claim 102 words

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.

Claim 6

Independent Claim 102 words

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.

Claim 7

Dependent Claim 26 words

The method as claimed in claim 4, wherein said step of annealing is performed at a temperature in a range of 580° C. to 750° C.

Claim 8

Dependent Claim 24 words

The method as claimed in claim 4, wherein said step of cleaning is performed by subjecting said amorphous silicon layer to hydrofluoric acid (HF).

Claim 9

Independent Claim 118 words

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.

Claim 10

Independent Claim 118 words

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.

Claim 11

Dependent Claim 41 words

The method as claimed in claim 7, further comprising the step of cleaning a surface of said amorphous silicon layer before the step of annealing, said amorphous silicon layer being thereby annealed after said amorphous silicon layer has an oxide-free surface.

Claim 12

Dependent Claim 19 words

The method as claimed in claim 8, wherein said step of cleaning is performed by a hydrofluoric acid (HF).

Claim 13

Dependent Claim 69 words

The method as claimed in claim 7, wherein said impurity-doped silicon layer having a top surface and a side surface, said amorphous silicon layer being formed on the top and side surfaces of said impurity-doped silicon layer to thereby having a top surface and a side surface, and said plurality of silicon grains being thereby grown from both of the top and side surfaces of said amorphous silicon layer.

Claim 14

Independent Claim 100 words

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.

Claim 15

Independent Claim 100 words

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.

Claim 16

Dependent Claim 26 words

The method as claimed in claim 11, wherein each of said amorphous silicon layers is cleaned to provide an oxide-free surface before the step of annealing.

Claim 17

Independent Claim 158 words

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.

Claim 18

Independent Claim 158 words

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.

Claim 19

Dependent Claim 19 words

The method as claimed in claim 13, wherein said step of cleaning is performed by a hydrofluoric acid (HF).

Claim 20

Independent Claim 139 words

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.

Claim 21

Independent Claim 139 words

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.

Claim 22

Dependent Claim 22 words

The method as claimed in claim 15, wherein a surface of said amorphous silicon is maintained in an oxide-free and carbon-free state.

Claim 23

Dependent Claim 20 words

The method as claimed in claim 16, wherein said annealing is performed in a vacuum higher than 1×10 -6 Torr.

Claim 24

Dependent Claim 16 words

The method as claimed in claim 16, wherein said annealing is performed in an inert gas.

Claim 25

Dependent Claim 25 words

The method as claimed in claim 15, wherein said annealing is carried out at a temperature in a range between 580° C. and 750° C.

Claim 26

Dependent Claim 37 words

The method as claimed in claim 15, wherein said step of forming said first electrode comprises the steps of: forming a polycrystalline silicon layer on a substrate; and selectively forming said amorphous silicon on said polycrystalline layer.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-11-24	2001-05-26	2001-11-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-11-24	2005-05-26	2005-11-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-11-24	2009-05-26	2009-11-25	$7700.00	Window Closed / Lapsed

Method for fabricating polycrystalline silicon having micro roughness on the surface

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