US5350709A — Method of doping a group III-V compound semicondu…

Claim 1

Independent Claim 87 words

A method of doping a Group III-V compound semiconductor with an impurity, comprising the steps of: successively depositing on a crystal of a Group III-V compound semiconductor an undoped silicon oxide film (an SiOx film) and a film for preventing the external diffusion of Group V atoms that constitute part of the crystal of the Group III-V compound semiconductor; and performing at least one heat treatment on the thus prepared sample to cause silicon (Si) in the SiOx film to diffuse into the Group III-V compound semiconductor.

Claim 2

Independent Claim 87 words

A method of doping a Group III-V compound semiconductor with an impurity, comprising the steps of: successively depositing on a crystal of a Group III-V compound semiconductor an undoped silicon oxide film (an SiOx film) and a film for preventing the external diffusion of Group V atoms that constitute part of the crystal of the Group III-V compound semiconductor; and performing at least one heat treatment on the thus prepared sample to cause silicon (Si) in the SiOx film to diffuse into the Group III-V compound semiconductor.

Claim 3

Dependent Claim 38 words

A method of doping according to claim 1, wherein the Group III-V compound semiconductor comprises at least one material selected from the group consisting of GaAs system, InP system, AlAs system, AlGaAs system, InGaAs system, and InAlAs system.

Claim 4

Dependent Claim 43 words

A method of doping according to claim 1, wherein the film for preventing the external diffusion of Group V atoms is at least one selected from the group consisting of an SiN film, an AlN film, a WSi film, and a WSiN film.

Claim 5

Dependent Claim 18 words

A method of doping according to claim 1, wherein x in the SiOx film is less than 2.

Claim 6

Dependent Claim 49 words

A method of doping according to claim 1, further comprising the step of: after depositing the two films, leaving the two films in a designated region unremoved or leaving the film for preventing the external diffusion of Group V atoms in a designated region and the SiOx film unremoved.

Claim 7

Dependent Claim 38 words

A method of doping according to claim 1, wherein when depositing the two films, the thickness and/or properties of at least either one of the films are varied to modify the diffusion profile of Si after heat treatment.

Claim 8

Independent Claim 162 words

A method of fabricating a field-effect transistor having a lightly doped layer formed directly below a gate electrode, a highly doped layer forming a source and a drain region, and a moderately doped layer formed between the lightly doped and highly doped layers, the three layers being formed at the surface of a substrate of a Group III-V compound, comprising the steps of: forming the lightly doped layer at the surface of the substrate; forming the gate electrode on the center portion of the upper surface of the lightly doped layer; forming an undoped SiOx film and a Group V atom diffusion stop film over the upper surface of the lightly doped layer; forming the highly doped layer at each end of the lightly doped layer; forming by heat treatment the moderately doped layer in the lightly doped layer except the portion thereof directly below the gate electrode; and forming an ohmic electrode on the upper surface of the highly doped layer.

Claim 9

Independent Claim 162 words

A method of fabricating a field-effect transistor having a lightly doped layer formed directly below a gate electrode, a highly doped layer forming a source and a drain region, and a moderately doped layer formed between the lightly doped and highly doped layers, the three layers being formed at the surface of a substrate of a Group III-V compound, comprising the steps of: forming the lightly doped layer at the surface of the substrate; forming the gate electrode on the center portion of the upper surface of the lightly doped layer; forming an undoped SiOx film and a Group V atom diffusion stop film over the upper surface of the lightly doped layer; forming the highly doped layer at each end of the lightly doped layer; forming by heat treatment the moderately doped layer in the lightly doped layer except the portion thereof directly below the gate electrode; and forming an ohmic electrode on the upper surface of the highly doped layer.

Claim 10

Independent Claim 126 words

A method of fabricating a field-effect transistor on a Group III-V compound semiconductor substrate, comprising the steps of: selectively etching the compound semiconductor substrate in a substantially vertical direction; forming a composite film consisting of an undoped SiOx film and a Group V atom diffusion stop film over the horizontal and vertical surfaces of the selectively etched compound semiconductor substrate; forming an active layer by heat-treating the compound semiconductor substrate with the composite film formed thereon and by diffusing Si into the compound semiconductor substrate; forming a source electrode and a drain electrode on the active layer formed on the horizontal surface of the compound semiconductor substrate; and forming a gate electrode on the active layer formed on the vertical surface of the compound semiconductor substrate.

Claim 11

Independent Claim 126 words

A method of fabricating a field-effect transistor on a Group III-V compound semiconductor substrate, comprising the steps of: selectively etching the compound semiconductor substrate in a substantially vertical direction; forming a composite film consisting of an undoped SiOx film and a Group V atom diffusion stop film over the horizontal and vertical surfaces of the selectively etched compound semiconductor substrate; forming an active layer by heat-treating the compound semiconductor substrate with the composite film formed thereon and by diffusing Si into the compound semiconductor substrate; forming a source electrode and a drain electrode on the active layer formed on the horizontal surface of the compound semiconductor substrate; and forming a gate electrode on the active layer formed on the vertical surface of the compound semiconductor substrate.

Claim 12

Independent Claim 132 words

A method of fabricating a field-effect transistor having an active layer and an impurity-diffused layer formed in a Group III-V compound semiconductor substrate, with a gate electrode formed on the active layer and a source electrode and a drain electrode formed on the impurity-diffused layer, comprising the steps of: forming a stepped portion by etching the Group III-V compound semiconductor substrate; forming the active layer in the upper part of the stepped portion; forming a composite film consisting of an undoped SiOx film and a Group V atom diffusion stop film on the side and lower parts of the stepped portion of the compound semiconductor substrate; and forming the impurity-diffused layer by heat-treating the compound semiconductor substrate with the composite film formed thereon and by diffusing Si into the compound semiconductor substrate.

Claim 13

Independent Claim 132 words

A method of fabricating a field-effect transistor having an active layer and an impurity-diffused layer formed in a Group III-V compound semiconductor substrate, with a gate electrode formed on the active layer and a source electrode and a drain electrode formed on the impurity-diffused layer, comprising the steps of: forming a stepped portion by etching the Group III-V compound semiconductor substrate; forming the active layer in the upper part of the stepped portion; forming a composite film consisting of an undoped SiOx film and a Group V atom diffusion stop film on the side and lower parts of the stepped portion of the compound semiconductor substrate; and forming the impurity-diffused layer by heat-treating the compound semiconductor substrate with the composite film formed thereon and by diffusing Si into the compound semiconductor substrate.

Claim 14

Independent Claim 123 words

A method of forming a field-effect transistor having a plurality of doped layers of different impurity concentrations formed in a Group III-V compound semiconductor substrate, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor substrate; forming a doped layer by diffusing Si into the Group III-V compound semiconductor substrate by heat treatment; removing the SiOx film and the he Group V atom diffusion stop film in a designated region; and performing heat treatment again and forming, in a region covered by the SiOx film and the Group V atom diffusion stop film, a doped layer having a higher impurity concentration than the first formed doped layer.

Claim 15

Independent Claim 123 words

A method of forming a field-effect transistor having a plurality of doped layers of different impurity concentrations formed in a Group III-V compound semiconductor substrate, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor substrate; forming a doped layer by diffusing Si into the Group III-V compound semiconductor substrate by heat treatment; removing the SiOx film and the he Group V atom diffusion stop film in a designated region; and performing heat treatment again and forming, in a region covered by the SiOx film and the Group V atom diffusion stop film, a doped layer having a higher impurity concentration than the first formed doped layer.

Claim 16

Independent Claim 91 words

A method of fabricating a semiconductor circuit device having conductive layers of different resistivities by doping a Group III-V compound semiconductor with an impurity, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor; reducing the thickness of the Group V atom diffusion stop film over a region where a conductive layer of higher resistivity is to be formed; and diffusing Si into the Group III-V compound semiconductor by heat-treating the Group III-V compound semiconductor.

Claim 17

Independent Claim 91 words

A method of fabricating a semiconductor circuit device having conductive layers of different resistivities by doping a Group III-V compound semiconductor with an impurity, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor; reducing the thickness of the Group V atom diffusion stop film over a region where a conductive layer of higher resistivity is to be formed; and diffusing Si into the Group III-V compound semiconductor by heat-treating the Group III-V compound semiconductor.

Claim 18

Independent Claim 112 words

A method of fabricating a semiconductor circuit device having conductive layers of different resistivities by doping a Group III-V compound semiconductor with an impurity, comprising the steps of: constructing a heterojunction layer by forming a wide-gap semiconductor layer on an undoped narrow-gap semiconductor layer which is the Group III-V compound semiconductor; forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the heterojunction layer; reducing the thickness of the Group V atom diffusion stop film over a region where a conductive layer of higher resistivity is to be formed; and diffusing Si into the Group III-V compound semiconductor by heat-treating the Group III-V compound semiconductor.

Claim 19

Independent Claim 112 words

A method of fabricating a semiconductor circuit device having conductive layers of different resistivities by doping a Group III-V compound semiconductor with an impurity, comprising the steps of: constructing a heterojunction layer by forming a wide-gap semiconductor layer on an undoped narrow-gap semiconductor layer which is the Group III-V compound semiconductor; forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the heterojunction layer; reducing the thickness of the Group V atom diffusion stop film over a region where a conductive layer of higher resistivity is to be formed; and diffusing Si into the Group III-V compound semiconductor by heat-treating the Group III-V compound semiconductor.

Claim 20

Independent Claim 105 words

A method of fabricating a field-effect transistor having a doped layer formed in a Group III-V compound semiconductor layer as a channel layer or an electron supply layer, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor layer; forming the doped layer by diffusing Si into the Group III-V compound semiconductor layer by heat treatment; and subjecting the doped layer to heat treatment and causing Si in the doped layer to further diffuse into the Group III-V compound semiconductor layer to increase the thickness of the doped layer.

Claim 21

Independent Claim 105 words

A method of fabricating a field-effect transistor having a doped layer formed in a Group III-V compound semiconductor layer as a channel layer or an electron supply layer, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor layer; forming the doped layer by diffusing Si into the Group III-V compound semiconductor layer by heat treatment; and subjecting the doped layer to heat treatment and causing Si in the doped layer to further diffuse into the Group III-V compound semiconductor layer to increase the thickness of the doped layer.

Claim 22

Independent Claim 77 words

A method of forming a one-dimensional or two-dimensional electric conductive region by diffusing an impurity into a Group III-V compound semiconductor, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor; removing the Group V diffusion stop film everywhere except where the electric conductive region is to be formed; and diffusing Si into the Group III-V compound semiconductor by heat treatment.

Claim 23

Independent Claim 77 words

A method of forming a one-dimensional or two-dimensional electric conductive region by diffusing an impurity into a Group III-V compound semiconductor, comprising the steps of: forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the Group III-V compound semiconductor; removing the Group V diffusion stop film everywhere except where the electric conductive region is to be formed; and diffusing Si into the Group III-V compound semiconductor by heat treatment.

Claim 24

Independent Claim 109 words

A method of forming a quantum wire, comprising the steps of: forming an Si diffusion stop layer on a Group III-V compound semiconductor substrate and thereby forming a step; forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the substrate and the Si diffusion stop layer; removing the SiOx film and the Group V atom diffusion stop film everywhere except the portions thereof formed on the sidewall of the step; and heating the thus processed substrate and thereby causing Si to diffuse from the SiOx film into the Group III-V compound semiconductor substrate across their interface, to form a quantum wire.

Claim 25

Independent Claim 109 words

A method of forming a quantum wire, comprising the steps of: forming an Si diffusion stop layer on a Group III-V compound semiconductor substrate and thereby forming a step; forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the substrate and the Si diffusion stop layer; removing the SiOx film and the Group V atom diffusion stop film everywhere except the portions thereof formed on the sidewall of the step; and heating the thus processed substrate and thereby causing Si to diffuse from the SiOx film into the Group III-V compound semiconductor substrate across their interface, to form a quantum wire.

Claim 26

Independent Claim 113 words

A method of forming a quantum wire, comprising the steps of: forming all undoped SiOx film and a Group V atom diffusion stop film in this order on the surface of a substrate consisting of a plurality of dissimilar Group III-V compound semiconductors that are joined side by side to form the surface of the substrate; forming diffused areas of different depths in the Group III-V compound semiconductors by diffusing Si from the SiOx film by heat treatment; and removing the surface portion of the substrate so that the deeper diffused area remains in the substrate, and forming a quantum wire by a one-dimensional electron gas that occurs near the remaining diffused area.

Claim 27

Independent Claim 113 words

A method of forming a quantum wire, comprising the steps of: forming all undoped SiOx film and a Group V atom diffusion stop film in this order on the surface of a substrate consisting of a plurality of dissimilar Group III-V compound semiconductors that are joined side by side to form the surface of the substrate; forming diffused areas of different depths in the Group III-V compound semiconductors by diffusing Si from the SiOx film by heat treatment; and removing the surface portion of the substrate so that the deeper diffused area remains in the substrate, and forming a quantum wire by a one-dimensional electron gas that occurs near the remaining diffused area.

Claim 28

Independent Claim 152 words

A method of forming a quantum wire in which the moving direction of carriers in a channel layer is one dimensional, comprising the steps of: forming successively a narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate; forming the wide-gap semiconductor layer into a sawtooth-like cross section using an etching technique that utilizes the dependence of etching on the surface orientation of the wide-gap semiconductor layer; forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the wide-gap semiconductor layer formed in a sawtooth shape; forming a doped layer by performing heat treatment and diffusing Si into the surface of the wide-gap semiconductor layer; and forming a channel layer, and hence a quantum wire, only in the region of the narrow-gap semiconductor layer that lies directly below each trough of the sawtooth-shaped doped layer.

Claim 29

Independent Claim 152 words

A method of forming a quantum wire in which the moving direction of carriers in a channel layer is one dimensional, comprising the steps of: forming successively a narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate; forming the wide-gap semiconductor layer into a sawtooth-like cross section using an etching technique that utilizes the dependence of etching on the surface orientation of the wide-gap semiconductor layer; forming an undoped SiOx film and a Group V atom diffusion stop film in this order on the wide-gap semiconductor layer formed in a sawtooth shape; forming a doped layer by performing heat treatment and diffusing Si into the surface of the wide-gap semiconductor layer; and forming a channel layer, and hence a quantum wire, only in the region of the narrow-gap semiconductor layer that lies directly below each trough of the sawtooth-shaped doped layer.

Claim 30

Independent Claim 167 words

A method of forming a quantum box that confines carriers in a channel layer into a three-dimensional space, comprising the steps of: forming successively a narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate; forming the wide-gap semiconductor layer into a sawtooth shape using an etching technique that utilizes the dependence of etching on the surface orientation of the wide-gap semiconductor layer; forming an undoped SiOx film on the wide-gap semiconductor layer formed in a sawtooth shape; forming a Group V atom diffusion stop layer over a region where a quantum box is to be formed; forming a doped layer by performing heat treatment and diffusing Si into a designated region of the surface of the wide-gap semiconductor layer; and forming a channel layer, and hence a quantum box, only in the region of the narrow-gap semiconductor layer that lies directly below each trough of the sawtooth structure and that is covered by the doped layer.

Claim 31

Independent Claim 167 words

A method of forming a quantum box that confines carriers in a channel layer into a three-dimensional space, comprising the steps of: forming successively a narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate; forming the wide-gap semiconductor layer into a sawtooth shape using an etching technique that utilizes the dependence of etching on the surface orientation of the wide-gap semiconductor layer; forming an undoped SiOx film on the wide-gap semiconductor layer formed in a sawtooth shape; forming a Group V atom diffusion stop layer over a region where a quantum box is to be formed; forming a doped layer by performing heat treatment and diffusing Si into a designated region of the surface of the wide-gap semiconductor layer; and forming a channel layer, and hence a quantum box, only in the region of the narrow-gap semiconductor layer that lies directly below each trough of the sawtooth structure and that is covered by the doped layer.

Claim 32

Independent Claim 105 words

A method of fabricating a semiconductor circuit device having on a substrate a diffused layer containing areas of different impurity concentrations, with electrodes formed on the diffused layers, comprising the steps of: forming a Group III-V compound semiconductor layer on a substrate; forming on the semiconductor layer a plurality of shields, of different shielding widths, spaced apart by a prescribed distance; forming an undoped SiOx film and a Group V atom diffusion stop film in this order over the surfaces of the shields and the semiconductor surface except for the shields; and forming diffused layers by diffusing Si into the semiconductor layer by heat treatment.

Claim 33

Independent Claim 105 words

A method of fabricating a semiconductor circuit device having on a substrate a diffused layer containing areas of different impurity concentrations, with electrodes formed on the diffused layers, comprising the steps of: forming a Group III-V compound semiconductor layer on a substrate; forming on the semiconductor layer a plurality of shields, of different shielding widths, spaced apart by a prescribed distance; forming an undoped SiOx film and a Group V atom diffusion stop film in this order over the surfaces of the shields and the semiconductor surface except for the shields; and forming diffused layers by diffusing Si into the semiconductor layer by heat treatment.

Claim 34

Independent Claim 118 words

A method of fabricating a semiconductor integrated circuit by doping a Group III-V compound semiconductor with an impurity and forming a plurality of devices, comprising the steps of: forming an undoped narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate, thus constructing a heterojunction layer; exposing the narrow-gap semiconductor layer by removing the wide-gap semiconductor layer in a designated region; forming an undoped SiOx film and a Group V atom diffusion stop film in this order over the narrow-gap semiconductor layer and the wide-gap semiconductor layer; forming doped layers by diffusing Si into the Group III-V semiconductor by heat treatment; and forming electrodes on the doped layers.

Claim 35

Independent Claim 118 words

A method of fabricating a semiconductor integrated circuit by doping a Group III-V compound semiconductor with an impurity and forming a plurality of devices, comprising the steps of: forming an undoped narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate, thus constructing a heterojunction layer; exposing the narrow-gap semiconductor layer by removing the wide-gap semiconductor layer in a designated region; forming an undoped SiOx film and a Group V atom diffusion stop film in this order over the narrow-gap semiconductor layer and the wide-gap semiconductor layer; forming doped layers by diffusing Si into the Group III-V semiconductor by heat treatment; and forming electrodes on the doped layers.

Claim 36

Independent Claim 114 words

A method of fabricating a semiconductor integrated circuit by doping a Group III-V compound semiconductor with an impurity and forming a plurality of devices, comprising the steps of: forming an undoped narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate, thus constructing a heterojunction layer; partially removing the wide-gap semiconductor layer in the direction of its depth in a designated region; forming an SiOx film and a Group V atom diffusion stop film over the wide-gap semiconductor layer having a varying thickness; forming doped layers by diffusing Si into the Group III-V semiconductor by heat treatment; and forming electrodes on the doped layers.

Claim 37

Independent Claim 114 words

A method of fabricating a semiconductor integrated circuit by doping a Group III-V compound semiconductor with an impurity and forming a plurality of devices, comprising the steps of: forming an undoped narrow-gap semiconductor layer and a wide-gap semiconductor layer, both of Group III-V compound semiconductors, in this order on a substrate, thus constructing a heterojunction layer; partially removing the wide-gap semiconductor layer in the direction of its depth in a designated region; forming an SiOx film and a Group V atom diffusion stop film over the wide-gap semiconductor layer having a varying thickness; forming doped layers by diffusing Si into the Group III-V semiconductor by heat treatment; and forming electrodes on the doped layers.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-09-26	1998-03-28	1998-09-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-09-26	2002-03-28	2002-09-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-09-26	2006-03-28	2006-09-27	$7700.00	Window Closed / Lapsed

Method of doping a group III-V compound semiconductor

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