Etching method

Claim 1

A method of preparing a semiconductor device which device includes structural features shaped in three dimensions, which method comprises: (a) using MOVPE to grow one or more epitaxial layers onto a primary substrate; and (b) photoetching the product of (a) to create the structural features by removing predetermined regions of material, wherein steps (a) and (b) are performed in a MOVPE reactor without removing the workpiece therefrom between steps (a) and (b).

Claim 2

A method of preparing a semiconductor device which device includes structural features shaped in three dimensions, which method comprises: (a) using MOVPE to grow one or more epitaxial layers onto a primary substrate; and (b) photoetching the product of (a) to create the structural features by removing predetermined regions of material, wherein steps (a) and (b) are performed in a MOVPE reactor without removing the workpiece therefrom between steps (a) and (b).

Claim 3

A method of preparing a semiconductor device which device includes structural features shaped in three dimensions and wholly or partly covered by semiconductor overgrowth, which method comprises: (b) photoetching a semiconductor substrate to create precursors of the structural features by removing predetermined regions of material, and (c) using MOVPE to deposit one or more layers of epitaxial overgrowth onto the product of (b), wherein steps (b) and (c) are performed in a MOVPE reactor and without removing the workpiece therefrom between steps (b) and (c).

Claim 4

A method of preparing a semiconductor device which device includes structural features shaped in three dimensions and wholly or partly covered by semiconductor overgrowth, which method comprises: (b) photoetching a semiconductor substrate to create precursors of the structural features by removing predetermined regions of material, and (c) using MOVPE to deposit one or more layers of epitaxial overgrowth onto the product of (b), wherein steps (b) and (c) are performed in a MOVPE reactor and without removing the workpiece therefrom between steps (b) and (c).

Claim 5

A method of preparing a semiconductor device which device includes structural features shaped in three dimensions and covered by semiconductor overgrowth, which method comprises: (a) using MOVPE to grow one or more epitaxial layers onto a primary substrate; (b) photoetching the product of (a) to create precursors of the structural features by removing predetermined regions of material; and (c) using MOVPE to deposit one or more layers of epitaxial overgrowth onto the product of (b), wherein steps (a), (b) and (c) are performed in a MOVPE reactor without removing the workpiece therefrom.

Claim 6

A method of preparing a semiconductor device which device includes structural features shaped in three dimensions and covered by semiconductor overgrowth, which method comprises: (a) using MOVPE to grow one or more epitaxial layers onto a primary substrate; (b) photoetching the product of (a) to create precursors of the structural features by removing predetermined regions of material; and (c) using MOVPE to deposit one or more layers of epitaxial overgrowth onto the product of (b), wherein steps (a), (b) and (c) are performed in a MOVPE reactor without removing the workpiece therefrom.

Claim 7

A method according to any one of claims 1, 2 or 3 wherein a fugitive coating is applied before step (b) and said fugitive coating is selectively removed during step (b).

Claim 8

A method of growing a semiconductor device which device includes structural features shaped in three dimensions and covered by semiconductor overgrowth, which method comprises: (a) using MOVPE to grow one or more epitaxial layers onto a primary substrate; (a)(i) applying a fugitive coating to the product of (a); (b) photoetching the product of (a)(i) to create precursors of the structural features by removing predetermined regions of material, the fugitive coating applied in step (a)(i) being selectively removed as a preliminary to etching; (c)(i) using MOVPE to deposit one or more layers of epitaxial growth onto the product of (b) said growth being excluded on the regions still selectively coated with the coating applied in step (a)(i); (c)(ii) removing the remainder of said fugitive coating and (c)(iii) using MOVPE to apply secondary overgrowth to the product of step (c)(ii), where steps (a), (a)(i), (b), (c)(i), (c)(ii) and (c)(iii) are all performed in a MOVPE reactor without removing the workpiece therefrom.

Claim 9

A method of growing a semiconductor device which device includes structural features shaped in three dimensions and covered by semiconductor overgrowth, which method comprises: (a) using MOVPE to grow one or more epitaxial layers onto a primary substrate; (a)(i) applying a fugitive coating to the product of (a); (b) photoetching the product of (a)(i) to create precursors of the structural features by removing predetermined regions of material, the fugitive coating applied in step (a)(i) being selectively removed as a preliminary to etching; (c)(i) using MOVPE to deposit one or more layers of epitaxial growth onto the product of (b) said growth being excluded on the regions still selectively coated with the coating applied in step (a)(i); (c)(ii) removing the remainder of said fugitive coating and (c)(iii) using MOVPE to apply secondary overgrowth to the product of step (c)(ii), where steps (a), (a)(i), (b), (c)(i), (c)(ii) and (c)(iii) are all performed in a MOVPE reactor without removing the workpiece therefrom.

Claim 10

A method according to any one of the preceding claims in which the structural feature is a mesa or an optical path region and step (b) involves etching grooves on each side of the mesa.

Claim 11

A method of selectively etching a semiconductor substrate to remove material from first predetermined regions in preference to second predetermined regions which method comprises applying a fugitive coating to the surface of both said first and second predetermined regions and thereafter photoetching the workpiece to as to remove material preferentially from said first predetermined regions.

Claim 12

A method of selectively etching a semiconductor substrate to remove material from first predetermined regions in preference to second predetermined regions which method comprises applying a fugitive coating to the surface of both said first and second predetermined regions and thereafter photoetching the workpiece to as to remove material preferentially from said first predetermined regions.

Claim 15

A method according to any one of claims 7 to 9 wherein a first wavelength of illumination is used to remove the coating and a second wavelength is used to initiate the etch.

Claim 17

A method according to any one of claims 7 to 9 wherein the coating is selectively removed and the photoetching is initiated with the same wavelength of illumination whereby coating removal and commencement of etching occur substantially at the same time.

Claim 18

A method according to any one of claims 7 to 12, wherein the substrate is exposed to the precursor of an active etchant species and the initiating radiation is adapted to dissociate said precursor into said active etchant species.

Claim 23

A method according to any one of claims 7 to 17, in which the protective coating is an inorganic chloride or oxide.

Claim 26

A method according to any one of claims 7 to 20, wherein the substrate is formed of a semiconductor which contains at least one of In and Ga and at least one of P and As, wherein the method of applying the protective coating comprises producing a native oxide coating 1 to 20nm thick by exposing the surface of the substrate to an atmosphere which contains oxygen.

Claim 28

A method of etching a three dimensional pattern into the surface of a substrate which surface is protected by a fugitive coating wherein the surface is exposed to the precursor of an active etchant species and a predetermined pattern of radiation is applied to the surface of the substrate, said radiation being adapted to dissociate the precursor into active species and to remove the protective coating whereby material is removed where the radiation is applied so as to create said three dimensional pattern.

Claim 29

A method of etching a three dimensional pattern into the surface of a substrate which surface is protected by a fugitive coating wherein the surface is exposed to the precursor of an active etchant species and a predetermined pattern of radiation is applied to the surface of the substrate, said radiation being adapted to dissociate the precursor into active species and to remove the protective coating whereby material is removed where the radiation is applied so as to create said three dimensional pattern.

Claim 30

A method of etching a groove into the surface of a substrate which surface is protected by a fugitive coating wherein the surface is exposed to the precursor of an active etchant species and radiation is focussed along the intended groove, said radiation being adapted to dissociate the precursor into active species and to remove the protective coating whereby a groove is produced.

Claim 31

A method of etching a groove into the surface of a substrate which surface is protected by a fugitive coating wherein the surface is exposed to the precursor of an active etchant species and radiation is focussed along the intended groove, said radiation being adapted to dissociate the precursor into active species and to remove the protective coating whereby a groove is produced.

Claim 32

A method of etching grooves into the surface of a substrate which surface is protected by a fugitive coating wherein the surface is exposed to the precursor of an active etchant species and focused radiation is traversed along the intended grooves, said radiation being adapted to dissociate the precursor into active species and to remove the protective coating whereby grooves are produced along the paths traversed by the radiation.

Claim 33

A method of etching grooves into the surface of a substrate which surface is protected by a fugitive coating wherein the surface is exposed to the precursor of an active etchant species and focused radiation is traversed along the intended grooves, said radiation being adapted to dissociate the precursor into active species and to remove the protective coating whereby grooves are produced along the paths traversed by the radiation.