EP0356037A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of making an electro-optical device with inverted transparent substrate
Assignee: HP Inc
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Filing: 1989-08-02
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Granted: —
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Expires: 2009-08-02
Abstract
Abstract An electro-optical device with a transparent substrate (210) is produced by epitaxially first growing the device layers (220), followed by that of the transparent substrate layer (210) on an opaque wafer (200). The opaque wafer (200) is subsequently removed. The device layers (220) have dopants with sufficient low diffusivities that their electronic characteristics are not adversely affected by long exposure to elevated temperature during the growth of the transparent substrate layer. In a liquid phase epitaxy (LPE) method, a repeated temperature cycle technique is used where the temperature is repeatedly raised up each time after cooling to provide a large cooling range for growing a sufficiently thick substrate layer (210) or a series of device layers (220). In between growths and during the temperature heat-up periods, the device is stored within the LPE reactor. In other embodiments, the device is either temporarily removed from the LPE reactor or is transferred to another reactor. When a epitaxial layer is oxidizable, a non-oxidizable cap is temporarily grown on it in between growths and during the temperature heat-up periods. The cap is subsequently removed by melting back at an elevated temperature just prior to the growth of a next layer.
Inventors
- 👤 Louis Walter Cook
- 👤 Michael David Camras
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 21:08
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/811; H10H20/01; H10H20/011; H10H20/013; H10H20/822; H10H20/824
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
110 words
An electro-optical device comprising: a section (220) which converts electrical current to light or light to electrical current, said section including a semiconductor material doped with a dopant which has a diffusivity smaller than that of zinc; and a substrate (210) adjacent to the section (220), said substrate (210) being substantially transparent to the light to be converted or emitted by the section (220), said substrate and the section having been grown epitaxially from a substrate (200) which is opaque to the light to be converted or emitted by the section, wherein the section (220) is grown before the transparent substrate (210) and the opaque substrate (200) is subsequently removed.
Claim 2
Dependent Claim
110 words
An electro-optical device comprising: a section (220) which converts electrical current to light or light to electrical current, said section including a semiconductor material doped with a dopant which has a diffusivity smaller than that of zinc; and a substrate (210) adjacent to the section (220), said substrate (210) being substantially transparent to the light to be converted or emitted by the section (220), said substrate and the section having been grown epitaxially from a substrate (200) which is opaque to the light to be converted or emitted by the section, wherein the section (220) is grown before the transparent substrate (210) and the opaque substrate (200) is subsequently removed.
Claim 3
Dependent Claim
59 words
The device of claim 1, wherein said section (226) is a light emitting diode including a first p-type layer (226) and a second n-type layer (228) adjacent to each other, the band gaps of the two layers being such that the p-type layer emits light by converting electrical current to light, said p-type layer being doped with the dopant.
Claim 4
Dependent Claim
39 words
The device of claim 2, wherein said section includes a second p-type layer (224) adjacent to the first p-type layer (226), said first and second p-type layers forming another heterojunction (225) so that the device is a double heterostructure.
Claim 5
Dependent Claim
25 words
The device of claim 1, wherein said opaque substrate (200) is composed of GaAs, and the section (220) and transparent substrate (210) composed of AlGaAs.
Claim 6
Dependent Claim
43 words
The device of claim 4, said device having been grown by a liquid phase epitaxial process wherein AlGaAs is epitaxially grown onto the opaque substrate (200) to form the device, wherein the aluminum content in the substrate (200) decreases in the growth direction.
Claim 7
Dependent Claim
10 words
The device of claim 1, wherein said dopant is magnesium.
Claim 8
Dependent Claim
26 words
The device of claim 1, wherein said opaque substrate (200) is composed of GaAs, and the section (220) and the transparent substrate (210) composed of AlInGaP.
Claim 9
Dependent Claim
18 words
The device of claim 1, wherein the opaque substrate (200) has a dislocation density less than about 10⁵/sq.cm.
Claim 10
Independent Claim
79 words
A method for growing an electro-optical device comprising: growing epitaxially onto a first substrate (200) a section (220) which converts electrical current to light or light to electrical current, said first substrate (200) being substantially opaque to the light converted or emitted by the section (220); growing epitaxially onto the section (220) a second substrate (210), said second substrate (210) being substantially transparent to the light converted or emitted by the section (220); and removing the first substrate (200).
Claim 11
Independent Claim
79 words
A method for growing an electro-optical device comprising: growing epitaxially onto a first substrate (200) a section (220) which converts electrical current to light or light to electrical current, said first substrate (200) being substantially opaque to the light converted or emitted by the section (220); growing epitaxially onto the section (220) a second substrate (210), said second substrate (210) being substantially transparent to the light converted or emitted by the section (220); and removing the first substrate (200).
Claim 12
Dependent Claim
23 words
The method of claim 9, further comprising doping the section (220) with a dopant which has a diffusivity smaller than that of zinc.
Claim 13
Dependent Claim
28 words
The method of claim 10, wherein the growing and doping steps are accomplished by a cool down liquid phase epitaxial process employing a melt which includes the dopant.
Claim 14
Independent Claim
126 words
A method for growing layered semiconductor structures by means of an oven and at least one melt, comprising: heating a material in the oven to a predetermined temperature so that the material will melt to form at least a first melt; bringing a substrate (200) in the oven in contact with the first melt; cooling the first melt to epitaxially grow a first layer onto the substrate (200); separating the wafer and first layer from said one melt without withdrawing the wafer and layer from the oven; increasing the temperature in the oven so that the first or a different melt has a predetermined composition; and bringing the substrate (200) and grown layer thereon into contact with the first or different melt to grow another layer.
Claim 15
Independent Claim
126 words
A method for growing layered semiconductor structures by means of an oven and at least one melt, comprising: heating a material in the oven to a predetermined temperature so that the material will melt to form at least a first melt; bringing a substrate (200) in the oven in contact with the first melt; cooling the first melt to epitaxially grow a first layer onto the substrate (200); separating the wafer and first layer from said one melt without withdrawing the wafer and layer from the oven; increasing the temperature in the oven so that the first or a different melt has a predetermined composition; and bringing the substrate (200) and grown layer thereon into contact with the first or different melt to grow another layer.
Claim 16
Dependent Claim
79 words
The method of claim 12, wherein the first layer contains an oxidizable component, said method further comprising the steps of: bringing said first layer in contact with a second melt immediately after separating the first layer from the first melt; cooling the second melt to grow a second non-oxidizable cap layer onto said first layer to prevent oxidation of the first layer when it is separated from the first and second melts and during the subsequent temperature increasing step.
Claim 17
Dependent Claim
101 words
The method of claim 12, wherein the method is applied using a multibin slider boat arrangement in the oven, said arrangement including a plurality of melt bins for holding growth melts, where layers are grown onto a substrate by sliding the wafer into contact with the growth melts in the bins in a predetermined direction during which time the oven is being cooled continuously, wherein the separating step is accomplished by leaving the melt bin following the bin holding the one melt in the predetermined direction empty and sliding the substrate and the grown layer into contact with the empty bin.
Claim 18
Independent Claim
160 words
A method for growing layered semiconductor structures comprising: heating materials to predetermined temperatures so that the materials will melt to form at least two melts; bringing a substrate (200) in the oven in contact with a first melt; cooling the melt to epitaxially grow a first layer onto the substrate (200), said layer containing an oxidizable component; separating the substrate (200) and first layer from said one melt; bringing said first layer in contact with a second melt; cooling the second melt to grow a second non-oxidizable cap layer onto said first layer to prevent oxidation of the first layer when it is separated from the first melt; bringing the substrate (200) and grown layer thereon into contact with a third melt, wherein the third melt is at a temperature sufficient to melt back the second layer and so that the third melt has predetermined compositions; and cooling the third melt to grow a third layer onto said first layer.
Claim 19
Independent Claim
160 words
A method for growing layered semiconductor structures comprising: heating materials to predetermined temperatures so that the materials will melt to form at least two melts; bringing a substrate (200) in the oven in contact with a first melt; cooling the melt to epitaxially grow a first layer onto the substrate (200), said layer containing an oxidizable component; separating the substrate (200) and first layer from said one melt; bringing said first layer in contact with a second melt; cooling the second melt to grow a second non-oxidizable cap layer onto said first layer to prevent oxidation of the first layer when it is separated from the first melt; bringing the substrate (200) and grown layer thereon into contact with a third melt, wherein the third melt is at a temperature sufficient to melt back the second layer and so that the third melt has predetermined compositions; and cooling the third melt to grow a third layer onto said first layer.
Claim 20
Dependent Claim
34 words
The method of claim 15, wherein the heating and cooling are accomplished by one oven, and the steps of the method are performed with the substrate and the grown layers remaining in the oven.
Claim 21
Dependent Claim
68 words
The method of claim 15, wherein the heating and cooling steps for growing the first and second layers are accomplished by one oven, said method further comprising the step of removing the substrate (200) and the first and second layers from the oven, and the step of subsequently placing the substrate (200) and the first and second layers into the same or different oven heated to said temperature.
Claim 22
Independent Claim
290 words
A method for growing a semiconductor structure with n layers, n being a positive integer, by means of a multibin arrangement with a plurality of bins aligned along a line, said bins suitable for holding n melts for growing n epitaxial layers, wherein layers are grown successively onto a substrate (200) by pushing a boat containing a substrate along the line so that the substrate comes into contact successively with the n melts held by the bins, said method comprising: filing n bins with suitable materials for creating the melts in the bins so that there is at least one empty bin between two filled bins along the line; heating the arrangement to melt the materials; pushing the boat along the line and stopping at each bin so that the boat and the substrate (200) come into contact successively with the melts; cooling the melts when the substrate (200) is in contact with each melt in bins preceding the empty bin to grow epitaxial layers on the substrate or a previously grown layer; and heating the melt in the bin follwing the empty bin to a predetermined temperature so that the melt therein has a desired composition when the substrate (200) is in communication with the empty bin; and pushing the boat until the wafer is in contact with the melt in the bin following the empty bin; and cooling the melt in the bin following the empty bin to grow a layer onto a previously grown layer, wherein the second heating step changes the composition of the melt so that the thickness of the layer grown when the substrate and any layers previously grown are in contact with the melt in the bin following the empty bin is increased.
Claim 23
Independent Claim
290 words
A method for growing a semiconductor structure with n layers, n being a positive integer, by means of a multibin arrangement with a plurality of bins aligned along a line, said bins suitable for holding n melts for growing n epitaxial layers, wherein layers are grown successively onto a substrate (200) by pushing a boat containing a substrate along the line so that the substrate comes into contact successively with the n melts held by the bins, said method comprising: filing n bins with suitable materials for creating the melts in the bins so that there is at least one empty bin between two filled bins along the line; heating the arrangement to melt the materials; pushing the boat along the line and stopping at each bin so that the boat and the substrate (200) come into contact successively with the melts; cooling the melts when the substrate (200) is in contact with each melt in bins preceding the empty bin to grow epitaxial layers on the substrate or a previously grown layer; and heating the melt in the bin follwing the empty bin to a predetermined temperature so that the melt therein has a desired composition when the substrate (200) is in communication with the empty bin; and pushing the boat until the wafer is in contact with the melt in the bin following the empty bin; and cooling the melt in the bin following the empty bin to grow a layer onto a previously grown layer, wherein the second heating step changes the composition of the melt so that the thickness of the layer grown when the substrate and any layers previously grown are in contact with the melt in the bin following the empty bin is increased.
Claim 24
Dependent Claim
60 words
The method of claim 18, wherein when the substrate (200) and any previously grown layers come into contact with the melt in the bin preceding the empty bin, the cooling of such melt in the first cooling step causes a non-oxidizable cap layer to be grown to prevent any previously grown layer from being oxidized during the subsequent heating step.
Claim 25
Dependent Claim
36 words
The method of claim 19, further comprising heating the melt in the bin following the empty bin before the second cooling step in order to melt the non-oxidizable cap layer before the subsequent layer is grown.
References Cited (Backward Citations)
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