US4264376A — Method for producing a nonvolatile memory device

Claim 1

Independent Claim 100 words

A method of producing a nonvolatile memory device of a metal-nitride-oxide-semiconductor type, comprising the steps of: forming a gate insulating film on a semiconductor substrate by forming a silicon dioxide layer on the substrate and then forming a silicon nitride layer on the silicon dioxide layer; depositing a gate electrode on said gate insulating film; forming a source and a drain in a surface region of said semiconductor substrate; forming a protective or passivation film on the entire resulting surface; and effecting a heat treatment of the substrate after the insulating film is formed thereon in an atmosphere including hydrogen.

Claim 2

Independent Claim 100 words

A method of producing a nonvolatile memory device of a metal-nitride-oxide-semiconductor type, comprising the steps of: forming a gate insulating film on a semiconductor substrate by forming a silicon dioxide layer on the substrate and then forming a silicon nitride layer on the silicon dioxide layer; depositing a gate electrode on said gate insulating film; forming a source and a drain in a surface region of said semiconductor substrate; forming a protective or passivation film on the entire resulting surface; and effecting a heat treatment of the substrate after the insulating film is formed thereon in an atmosphere including hydrogen.

Claim 3

Dependent Claim 28 words

A method as claimed in claim 1, wherein said gate electrode is made of a material selected from the group consisting of polycrystalline silicon and a refractory metal.

Claim 4

Dependent Claim 29 words

A method as claimed in claim 2, wherein said refractory metal is selected from the group consisting of Mo, W, Ta, Ti, Cr, Ni alloys and silicon compounds thereof.

Claim 5

Dependent Claim 28 words

A method as claimed in claim 2 or 3, wherein said source and drain are formed in a self-aligning manner with said gate electrode used as a mask.

Claim 6

Dependent Claim 27 words

A method as claimed in claim 1, 2 or 3, wherein said heat treatment in said hydrogen including atmosphere is performed before said protective film is formed.

Claim 7

Dependent Claim 28 words

A method as claimed in claim 1, 2 or 3, wherein said heat treatment in said hydrogen including atmosphere is performed after said protective film has been formed.

Claim 8

Dependent Claim 32 words

A method as claimed in claim 1, 2 or 3, wherein said heat treatment in said hydrogen including atmosphere is performed at temperatures ranging from about 700° C. to about 1200° C.

Claim 9

Dependent Claim 69 words

A method as claimed in claim 1, 2 or 3, wherein said heat treatment in said hydrogen including atmosphere is effected at a temperature not lower than a temperature which is about 100° C. lower than a temperature of any heat treatment of the method in a non-hydrogen atmosphere and an upper limit to said temperature of said heat treatment in said hydrogen including atmosphere is about 1200° C.

Claim 10

Dependent Claim 27 words

A method as claimed in claim 8, wherein the heat treatment in an atmosphere including hydrogen is effected after any other heat treatments in a non-hydrogen atmosphere.

Claim 11

Dependent Claim 26 words

A method as claimed in claim 1, 2 or 3, wherein said gate insulating film consists of a silicon dioxide film and a silicon nitride film.

Claim 12

Dependent Claim 28 words

A method as claimed in claim 1, 2 or 3, wherein said gate insulating film includes a second layer of silicon dioxide formed on the silicon nitride layer.

Claim 13

Dependent Claim 35 words

A method as claimed in claim 1, 2 or 3, wherein the heat treatment in the hydrogen including atmosphere is at a temperature greater than any heat treatment of the method in a non-hydrogen atmosphere.

Claim 14

Independent Claim 229 words

A method of producing a nonvolatile memory device of a metal-nitride-oxide-semiconductor type, comprising the steps of: (a) forming a silicon dioxide film on a semiconductor substrate, (b) removing a portion of the silicon dioxide film to expose the substrate, (c) forming a silicon dioxide film on the exposed surface of the substrate, (d) forming a silicon nitride film on the silicon dioxide film, (e) forming a refractory film on the silicon nitride layer, (f) etching a portion of the refractory film to form a gate, (g) forming a source and drain in the surface region of the semiconductor substrate, (h) forming a protective film over any exposed surface of the substrate and films thereon, and (i) heat treating the substrate having at least the silicon nitride film formed thereon in an atmosphere including hydrogen, said heat treating being effected at a temperature of not less than about 700° C. when any heat treatment of the method in a non-hydrogen atmosphere is not more than 1000° C. and being at a temperature not lower than a temperature which is about 100° C. less than or equal to a temperature of any heat treatment of the method in a non-hydrogen atmosphere when the heat treatment of the method in a non-hydrogen atmosphere is higher than 1000° C., the heat treatment in the atmosphere including hydrogen being less than about 1200° C.

Claim 15

Independent Claim 229 words

A method of producing a nonvolatile memory device of a metal-nitride-oxide-semiconductor type, comprising the steps of: (a) forming a silicon dioxide film on a semiconductor substrate, (b) removing a portion of the silicon dioxide film to expose the substrate, (c) forming a silicon dioxide film on the exposed surface of the substrate, (d) forming a silicon nitride film on the silicon dioxide film, (e) forming a refractory film on the silicon nitride layer, (f) etching a portion of the refractory film to form a gate, (g) forming a source and drain in the surface region of the semiconductor substrate, (h) forming a protective film over any exposed surface of the substrate and films thereon, and (i) heat treating the substrate having at least the silicon nitride film formed thereon in an atmosphere including hydrogen, said heat treating being effected at a temperature of not less than about 700° C. when any heat treatment of the method in a non-hydrogen atmosphere is not more than 1000° C. and being at a temperature not lower than a temperature which is about 100° C. less than or equal to a temperature of any heat treatment of the method in a non-hydrogen atmosphere when the heat treatment of the method in a non-hydrogen atmosphere is higher than 1000° C., the heat treatment in the atmosphere including hydrogen being less than about 1200° C.

Claim 16

Dependent Claim 26 words

A method as claimed in claim 13, wherein between steps (f) and (g) the silicon nitride layer is etched by using the gate as a mask.

Claim 17

Dependent Claim 27 words

A method as claimed in claim 13, wherein between steps (g) and (h) a silicon dioxide film is formed over the gate and source and drain regions.

Claim 18

Dependent Claim 26 words

A method as claimed in claim 13, wherein between steps (d) and (e) an additional film or silicon dioxide is formed on the silicon nitride film.

Claim 19

Dependent Claim 15 words

A method as claimed in claim 13, wherein step (i) is performed after step (d).

Claim 20

Dependent Claim 20 words

A method as claimed in claim 1, 2, 3 or 13, wherein the protective or passivation film comprises phosphosilicate glass.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-04-27	1984-10-27	1985-04-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-04-27	1988-10-27	1989-04-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-04-27	1992-10-27	1993-04-28	$7700.00	Window Closed / Lapsed

Method for producing a nonvolatile memory device

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