EP0171242A2 — Methods of making semiconductor light-emitting de…

Claim 1

Independent Claim 193 words

A method of making a semiconductive light-emitting device by forming, on a substrate (1) by epitaxial growth, a plurality of layers (61 to 65) of semiconductive compounds consisting of elements of groups III-V of the periodic table, the method being characterised by the steps of: heating the substrate (1) to a temperature of 580°C to 630°C; separately flowing a mixed gas of triethyl compounds of metals of group III and a gas of phosphine, wherein the ratio of phosphine to the triethyl compounds of metals of group III is at least 300:1; mixing said gases together immediately prior to the substrate (1), thereby forming a semiconductive layer of a selected composition comprising elements of group III-V on the substrate (1); and repeating the above procedure so as successively to form a plurality of layers (61 to 65) on the substrate (1), the plurality of layers (61 to 65) consisting of semiconductive compounds, each of which are represented by the formula: in which 0 is less than or equal to y is less than or equal to 1 and 0 is less than or equal to x is less than or equal to 1.

Claim 2

Independent Claim 193 words

A method of making a semiconductive light-emitting device by forming, on a substrate (1) by epitaxial growth, a plurality of layers (61 to 65) of semiconductive compounds consisting of elements of groups III-V of the periodic table, the method being characterised by the steps of: heating the substrate (1) to a temperature of 580°C to 630°C; separately flowing a mixed gas of triethyl compounds of metals of group III and a gas of phosphine, wherein the ratio of phosphine to the triethyl compounds of metals of group III is at least 300:1; mixing said gases together immediately prior to the substrate (1), thereby forming a semiconductive layer of a selected composition comprising elements of group III-V on the substrate (1); and repeating the above procedure so as successively to form a plurality of layers (61 to 65) on the substrate (1), the plurality of layers (61 to 65) consisting of semiconductive compounds, each of which are represented by the formula: in which 0 is less than or equal to y is less than or equal to 1 and 0 is less than or equal to x is less than or equal to 1.

Claim 3

Dependent Claim 26 words

A method according to claim 1 wherein selected layers of the plurality of layers (61 to 65) are doped with a dopant of Se or Zn.

Claim 4

Dependent Claim 29 words

A method according to claim 1 or claim 2 wherein said mixed gas of triethyl compounds is carried by a hydrogen carrier gas in a concentration less than 0.1%.

Claim 5

Dependent Claim 27 words

A method according to claim 1, claim 2 or claim 3 wherein said phosphine is carried by a hydrogen carrier gas in a concentration less than 10%.

Claim 6

Independent Claim 27 words

A method according to any one of the preceding claims wherein said mixture of gases flows over the substrate (1) at a flow rate of 80 cm/minute.

Claim 7

Dependent Claim 236 words

A vapour phase growth apparatus (10) for making a semiconductive light-emitting device by epitaxial growth of semiconductive compounds of elements of groups III-V, the apparatus (10) comprising: an atmospheric reaction furnace (10); and a substrate mount (13) positioned in said furnace (10), such that a gas passage (16) having an inlet (16a) is established between the substrate mount (13) and an inner side wall (lla) of the reaction furnace (11); characterised by: a first starting gas feed port (17) located at the inlet (16a) of the gas passage (16) and through which triethyl compounds of metals of group III of the periodic table are caused to flow; and a second starting gas feed port (18) located between the inlet (16a) of the gas passage (16) and the first starting material gas feed port (17) and for the flow of phosphine; the second starting gas feed port (18) being inclined with respect to the first starting gas feed port (17), the first and second starting gas feed ports (17, 18) having substantially the same shape and size, and a mixed gas of the triethyl compounds of metals of group III and the phosphine flowing from the first and second starting gas feed port (17, 18), respectively, and being mixed immediately upstream of a substrate (1) located near the inlet (16a) to the gas passage (16) so that the mixed gas flows over and along the substrate surface.

Claim 8

Dependent Claim 236 words

A vapour phase growth apparatus (10) for making a semiconductive light-emitting device by epitaxial growth of semiconductive compounds of elements of groups III-V, the apparatus (10) comprising: an atmospheric reaction furnace (10); and a substrate mount (13) positioned in said furnace (10), such that a gas passage (16) having an inlet (16a) is established between the substrate mount (13) and an inner side wall (lla) of the reaction furnace (11); characterised by: a first starting gas feed port (17) located at the inlet (16a) of the gas passage (16) and through which triethyl compounds of metals of group III of the periodic table are caused to flow; and a second starting gas feed port (18) located between the inlet (16a) of the gas passage (16) and the first starting material gas feed port (17) and for the flow of phosphine; the second starting gas feed port (18) being inclined with respect to the first starting gas feed port (17), the first and second starting gas feed ports (17, 18) having substantially the same shape and size, and a mixed gas of the triethyl compounds of metals of group III and the phosphine flowing from the first and second starting gas feed port (17, 18), respectively, and being mixed immediately upstream of a substrate (1) located near the inlet (16a) to the gas passage (16) so that the mixed gas flows over and along the substrate surface.

Claim 9

Dependent Claim 25 words

An apparatus (10) according to claim 6 further comprising heating means (14) for heating the substrate (1) to a temperature of from 580°C to 630°C.

Claim 10

Dependent Claim 20 words

An apparatus (10) according to claim 7 or claim 8 wherein said heating means (14) surrounds said reaction furnace (11)-

Claim 11

Dependent Claim 32 words

An apparatus (10) according to claim 6, claim 7 or claim 8 wherein the second starting gas feed port (18) is at right angles to the first starting gas feed port (17).

Claim 12

Independent Claim 30 words

An apparatus (10) according to any one of claims 6 to 9 wherein the first and second starting gas feed ports (17, 18) have substantially the same width and height.

Claim 13

Independent Claim 37 words

An apparatus (10) according to any one of claims 6 to 10 wherein said substrate mount 13 and a substrate (1) carried thereon are positioned below the lower surface of the first starting gas feed port (17).

Methods of making semiconductor light-emitting devices and vapour phase growth apparatus used for carrying out the methods

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