CN1160803C - Epitaxial growth chip used for infrared emitting diode and infrared emitting diode - Google Patents
Epitaxial growth chip used for infrared emitting diode and infrared emitting diode Download PDFInfo
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- CN1160803C CN1160803C CNB001182943A CN00118294A CN1160803C CN 1160803 C CN1160803 C CN 1160803C CN B001182943 A CNB001182943 A CN B001182943A CN 00118294 A CN00118294 A CN 00118294A CN 1160803 C CN1160803 C CN 1160803C
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- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 36
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 29
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 28
- 239000010703 silicon Substances 0.000 claims abstract description 28
- 239000000758 substrate Substances 0.000 claims abstract description 28
- 229910001218 Gallium arsenide Inorganic materials 0.000 claims abstract description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 13
- 239000001301 oxygen Substances 0.000 claims abstract description 13
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 13
- 239000010410 layer Substances 0.000 claims description 115
- 239000011247 coating layer Substances 0.000 claims description 85
- 239000005864 Sulphur Substances 0.000 claims description 32
- 239000012535 impurity Substances 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 17
- 239000007791 liquid phase Substances 0.000 claims description 6
- 229910052732 germanium Inorganic materials 0.000 claims description 4
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical group [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 3
- 238000010030 laminating Methods 0.000 claims description 2
- 239000013078 crystal Substances 0.000 abstract description 4
- 238000005253 cladding Methods 0.000 abstract 5
- 229910052717 sulfur Inorganic materials 0.000 abstract 2
- 239000011593 sulfur Substances 0.000 abstract 2
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- 229910021397 glassy carbon Inorganic materials 0.000 description 14
- 238000001816 cooling Methods 0.000 description 11
- 239000007789 gas Substances 0.000 description 11
- 238000004891 communication Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 8
- 239000002184 metal Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000003518 caustics Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000005204 segregation Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000009931 harmful effect Effects 0.000 description 3
- 238000003475 lamination Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- SWXQKHHHCFXQJF-UHFFFAOYSA-N azane;hydrogen peroxide Chemical compound [NH4+].[O-]O SWXQKHHHCFXQJF-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 2
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 235000011089 carbon dioxide Nutrition 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical compound S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 1
- 238000009210 therapy by ultrasound Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/26—Materials of the light emitting region
- H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/26—Materials of the light emitting region
- H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
- H01L33/305—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table characterised by the doping materials
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- Engineering & Computer Science (AREA)
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- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Led Devices (AREA)
Abstract
The present invention provides an epitaxial wafer comprising, on a p-type GaAs single-crystal substrate, a first p-type layer; a p-type cladding layer; a p-type active layer; and an n-type cladding layer, wherein the n-type cladding layer has a carrier concentration of 1x1017 to 1x1018 cm-3; a sulfur concentration of 3x1016 atoms/cm3 or less; and a thickness of 20-50 mum. The maximum silicon concentration in the portion of the p-type cladding layer within 2 mum of the interface between the p-type cladding layer and the first p-type layer is less than 1x1018 atoms/cm3; the concentration of carbon, sulfur, or oxygen in the first p-type layer is less than 1x1017 atoms/cm3. Thus, there can be produced an epitaxial wafer for fabricating an infrared LED exhibiting high emitted-light intensity with small variation.
Description
Technical field
The present invention relates to utilize the epitaxial wafer of the height output infrarede emitting diode that uses in ultrared optical communication apparatus and the space conveyer and use the infrarede emitting diode of this epitaxial wafer and optical communication, the space conveyer of these diodes of packing in making.
Background technology
Adopt Ga
1-xAl
xThe light-emitting diode (following slightly be designated as ' LED ') of As (0≤X<1) (following slightly be designated as ' GaAlAs ') based compound semiconductor just is being used as ultrared red light source and is being extensive use of.Infrared LED is used to optical communication and space and transmits, but is accompanied by the high capacity that transmits data, the long distanceization of transmitting range, and the requirement of the infrared LED that height is exported improves constantly.
In the past, for example film is grown making GaAlAs according to epitaxial growth method on the GaAs substrate was LED, but compared for the single heterojunction structure with membrane structure, the one side output of double-heterostructure (following brief note is ' a DH structure ') is high, in addition, by removing substrate, can further realize high outputization.
When the epitaxial growth structure (following brief note is ' DDH structure ') of substrate type is removed in making, in the common DH structure of epitaxial growth only, be that the p type coats the three-decker of (clad) layer, active layer, n type coating layer and removes in the structure of substrate, the thickness attenuation of goods, be difficult to carry out the processing in the element technology, pn knot problem of short-circuit can take place near the element side in the cream that uses when element and conductor bond simultaneously.In order to prevent short circuit, in the DH structure additional after being used for increasing substrate and removing the processing gross thickness and from element bottom surface to bonding part distance all round the epitaxial growth layer become the normal structure of DDH structure.All round the epitaxial growth layer designed like this, promptly band gap is wideer than active layer, does not absorb the emission light from active layer.In addition, this all round the epitaxial growth layer can be attached to the n type coating layer side of described DH structure, also can be attached to p type coating layer side, and, this all round the epitaxial growth layer needn't one be decided to be individual layer, also can make up a plurality of epitaxially grown layers.
By utilizing the DH structure to make the DDH structure, the luminous composition that is absorbed by substrate in the DH structure also can extract in element-external, and luminous output is improved, but for the current market demands of high request, not talkatively necessarily can obtain sufficient output.In addition, need the deviation of luminous output littler and the epitaxial wafer of stability characteristic (quality) arranged.
Summary of the invention
The object of the present invention is to provide to have the DDH structure, be used to make the epitaxial wafer of the infrared LED that output is high, output bias is few, and the infrared light-emitting component that uses described epitaxial wafer.
According to epitaxial wafer at infrared LED with DDH structure, the result who furthers investigate repeatedly that carry out the height outputization of utilizing the infrared LED that this epitaxial wafer makes and output bias reduction aspect, the inventor finds at a p type layer, p type coating layer, in the lamination technology of the epitaxial wafer that p type active layer and n type coating layer are formed, the sulphur atom of sneaking into as impurity in n type coating layer reduces luminous output, the luminous output that sulphur atom causes in the n type coating layer descends also closely related with the layer thickness of n type coating layer, begin to exist on the interface partly the situation of impurity high concentration segregation in the growth of p type coating layer, these segregations descend the luminous output of LED, and make output at random, impurity as p type coating layer growth beginning part, the harmful effect of silicon is big especially, if in this interface portion particularly from the interface to the maximum less than 1 * 10 of p type coating layer side 2 μ m with the silicon concentration the interior zone
18Atom/cm
3, LED output significantly improves so, in addition, can realize the reduction of luminous output bias, in addition, in the height outputization of LED, impurity and carrier concentration in the one p type layer are closely related, and as impurity, the harmful effect of carbon, sulphur and oxygen is very big, in addition, layer thickness on the thickness of p type coating layer at this moment optimum range arranged, if in the scope of 50~80 μ m, can be realized the height outputization of LED, in addition, the carrier concentration of a p type layer is 3 * 10
17~1 * 10
18Cm
-3Scope in better, as the alloy of p type active layer, under the situation of using Ge, have negative correlation between Ge concentration that comprises in the n type GaAlAs layer and the luminous output, thereby finished the present invention.
In other words, the epitaxial wafer of infrared diode of the present invention is used liquid phase epitaxial process sequential laminating the one p type layer (Ga on p type GaAs single crystalline substrate
1-x1Al
X1As, 0.13≤X1≤0.40), p type coating layer (Ga
1-x2Al
X2As, 0.23≤X2≤0.46), the p type active layer (Ga of emission wavelength in 850~900nm scope
1-x3Al
X3As, 0≤X3≤0.03) and n type coating layer (Ga
1-x4Al
X4As, 0.13≤X4≤0.40) after, removes this p type GaAs single crystalline substrate, it is characterized in that the carrier concentration of n type coating layer is 1 * 10
17~1 * 10
18Cm
-3In the scope, and sulphur concentration is 3 * 10
16Atom/m
3Below.
In described epitaxial wafer, the layer thickness of described n type coating layer is in the scope of 20~50 μ m.
In addition, described epitaxial wafer comprises that interface from this a p type coating layer and a p type layer is to the maximum less than 1 * 10 of p type coating layer side 2 μ m with silicon concentration the interior zone
18Atom/cm
3
And, the concentration less than 1 * 10 of carbon, sulphur and oxygen in the described p type layer of described epitaxial wafer
17Atom/cm
3, carrier concentration is 3 * 10
17Cm
-3~1 * 10
18Cm
-3
In addition, in described epitaxial wafer, the layer thickness of described p type coating layer is in the scope of 50~80 μ m.
And in described epitaxial wafer, the major impurity of p type active layer is under the situation of germanium, and the Ge concentration in the n type coating layer is 3 * 10
16Atom/cm
3Below.
And, present invention resides in the infrarede emitting diode that electrode is set on the described epitaxial wafer and optical communication apparatus and space conveyer that these infrarede emitting diodes are housed.
As mentioned above, if the carrier concentration of n type coating layer is 1 * 10
17~1 * 10
18Cm
-3, sulphur concentration is 3 * 10
16Atom/cm
3Below, layer thickness is 20~50 μ m, can make the epitaxial wafer and the LED that can make the high LED of output so.
Particularly begin the silicon concentration maximum less than 1 * 10 of part by the growth of p type coating layer
18Atom/cm
3, carbon, sulphur and oxygen concentration less than 1 * 10 in the p type GaAlAs layer
17Atom/cm
3, the Ge concentration in the n type coating layer is 3 * 10
16Atom/cm
3Below, can make few epitaxial wafer and the LED of the high deviation of output.
In addition, if the layer thickness of p type coating layer in the scope of 50~80 μ m, can be made the epitaxial wafer and the LED of higher output.And the carrier concentration by making a p type GaAlAs layer is 3 * 10
17~1 * 10
18Cm
-3Scope in, can provide VF is reduced, export higher epitaxial wafer and LED.
Therefore, pack in optical communication apparatus, the space conveyer etc., can provide and Large Volume Data transmits, long-range data transmits corresponding communicator by the LED that these luminous outputs are high.
Other purpose of the present invention, further feature can become clear and definite in the following detailed description of reference accompanying drawing.
Description of drawings
Fig. 1 is the schematic diagram of the epitaxial wafer structure of expression infrared LED of the present invention.
Fig. 2 is a schematic diagram of making the slip boat method film formation device of epitaxial wafer of the present invention.
Fig. 3 is the graph of relation that sulphur concentration, carrier concentration and the LED in the n type coating layer of the above-mentioned epitaxial wafer of expression exports.
Fig. 4 is the chart of the silicon concentration section of expression the one p type GaAlAs layer and p type coating layer near interface.
Fig. 5 is the chart of expression silicon peak concentration and LED output relation.
Fig. 6 be expression in the one p type GaAlAs layer concentration of carbon and the chart of LED output relation.
Fig. 7 be expression in the one p type GaAlAs layer sulphur concentration and the chart of LED output relation.
Fig. 8 be expression in the one p type GaAlAs layer oxygen concentration and the figure of LED output relation.
Fig. 9 is the Ge concentration in the expression n type coating layer and the chart of LED output relation.
Embodiment
Fig. 1 is the schematic diagram of basic structure of the epitaxial wafer of expression infraluminescence LED of the present invention, by on p type GaAs single crystalline substrate 1 with liquid-phase growth method lamination the one p type layer 2 (Ga in turn
1-x1Al
X1As, 0.13≤X1≤0.40), p type coating layer 3 (Ga
1-x2Al
X2As, 0.23≤X2≤0.46), the p type active layer 4 (Gas of emission wavelength in 85~900nm scope
1-x3Al
X3As, 0≤X3≤0.03) and n type coating layer 5 (Ga
1-x4Al
X4As, 0.13≤X4≤0.40) after, removes above-mentioned p type GaAs single crystalline substrate 1 at last and obtain.
In the present invention, in the epitaxial wafer of the infraluminescence LED of this structure, the carrier concentration of n type coating layer is 1 * 10
17Cm
-3More than and 1 * 10
18Cm
-3Below, 2 * 10
17Cm
-3More than and 6 * 10
17Cm
-3Below better, and the sulphur concentration in the n type coating layer is 3 * 10
16Cm
-3Below, 1 * 10
16Cm
-3Below better.
The inventor finds in the epitaxial wafer of LED, between the sulphur concentration in the n type coating layer, carrier concentration and the luminous output dependency relation to be arranged, and by making sulphur concentration in the n type coating layer, carrier concentration in above-mentioned scope, can realize the raising of luminous output.Can think that its reason is, the sulphur that enters in the n type coating layer is intervened the formation of non-luminescence center under the influence of carrier concentration.
Though deliberately do not add sulphur in n type coating layer, impurity is sneaked in the grower system easily in the process of rheotaxial growth.Sneak into the reason of grower as sulphur, can consider the raw material that in epitaxial growth, use and the impurity of atmosphere gas, also have the attachment of grower etc. in addition.In order to prevent sneaking into of they, in the GaAs single crystalline substrate of in epitaxial growth, using and the preceding operation of GaAs polycrystalline, adopt the processing of high-purity corrosive agent, after carrying out corrosion treatment, utilize pure water to clean fully, as required, carry out ultrasonic Treatment etc.In addition, the atmosphere gas such as argon that form the no hydrogen of epitaxial growth atmosphere use high-pure gas, and, utilize the gas purification device to improve purity, prevent sneaking into of impurity.
In addition, before epitaxial growth was implemented, the sky that carried out under about 1400 ℃ in hydrogen chloride gas atmosphere 1 hour by epitaxial growth device burnt, and can realize the reduction of the sulphur concentration of n type coating layer expeditiously.Can think that its reason is, burn by this sky and handle that graphite material system commonly used in the reaction vessel is purified, the sulphur that adheres to etc. is removed expeditiously.Have again, the atmosphere gas coupling part of when this is grown, using, for example in epitaxially grown layer grower shown in Figure 2, epitaxial growth device refers to the integral body of this grower.
Having, in n type coating layer 5 of the present invention, is 3 * 10 at sulphur concentration again
16Cm
-3Under the following condition, if the carrier concentration of n type coating layer is than 1 * 10
18Cm
-3Height, the defective that causes of alloy increases so, and the decline of luminous output takes place.In addition, if the carrier concentration of n type coating layer than 1 * 10
17Cm
-3Low, can not satisfy the characteristic that requires of the high LED of positive direction voltage so.
In the present invention, it is following just passable that the layer thickness of said n type coating layer 5 reaches the above 50 μ m of 20 μ m.Layer thickness for n type coating layer, though thin thickness helps the light of few absorption from active layer 4, if but the layer thickness of n type coating layer is thinner than 20 μ m, so when constituting LED, the electric current that flows into from surface electrode is not extended to component periphery and concentrates on central authorities, it is low to become luminous output, the big LED of energising deterioration.In addition,, increase by luminous light absorption so, can find that output descends if layer thickness is thicker than 50 μ m.Therefore, the layer thickness scope of n type coating layer 5 can if reach below the above 40 μ m of 30l μ m, can be made the high infrared LED of luminous output so below 50 μ m more than the 20 μ m.
In the present invention, from the interface of a p type coating layer 3 and a p type layer 2 to the maximum less than 1 * 10 of p type coating layer side 2 μ m with the silicon concentration the interior zone
18Atom/cm
3Just can.
Even beginning the part cooling rate, the growth of p type coating layer 3 necessarily still becomes unstable because of the unsteadiness speed of growth of the degree of supersaturation of melt, the situation that the segregation of impurity high concentration is arranged in interface portion, this situation reduces the luminous output of LED, and finds to make output at random.To the result that these impurity are further discussed, the inventor judges that the influence of silicon is big especially, finds by make the maximum less than 1 * 10 of silicon concentration in this interface portion
18Cm
-3, LED output significantly improves, and in addition, can realize that the deviation of luminous output reduces.
In addition, the inventor finds that in the height outputization of LED, the impurity in the p type layer 2 is closely related with carrier concentration, and as impurity, the harmful effect of carbon, sulphur and oxygen is big.Therefore, judge these impurity less thaies 1 * 10
17Atom/cm
3Better.
And the inventor finds in the infrared LED of DDH structure, on the thickness of p type coating layer 3 optimum range is arranged, and by making this thickness below the above 80l μ of 50 μ m m, can realize the height output of LED, in addition, and the carrier concentration less than 1 * 10 of a p type layer 2
18Cm
-3Just can, and, in order to make positive direction voltage (VF) the not enough 2.1V of the square LED of 350l μ m when the 200mA, reach 3 * 10
17Cm
-3More than better.
In the present invention, be under the situation of germanium at the major impurity of p type active layer 2, the Ge concentration in the n type coating layer 5 is 3 * 10
16Atom/cm
3Below just can.
Ge uses as the impurity of p type active layer 2, but is not deliberately to be added in the n type layer.Therefore, can think, in epitaxial growth layer growth process, the Ga solution that comprises the p type active layer growth usefulness of Ge is brought into the Ga solution of n type layer growth, and the Ge diffusion of the Ga solution of using to n type layer growth from the Ga solution of the p type active layer growth usefulness that comprises Ge is to sneak into the source to the Ge of n type layer.
As the growing method of above-mentioned epitaxial wafer, can use liquid phase growing method and method of vapor-phase growing, but the liquid phase growing method that especially uses slip boat shown in Figure 2 slowly to lower the temperature is better.
Use Fig. 2 to illustrate in greater detail the present invention.P type GaAs substrate 11 (1) in packing groove 12 into, the substrate of slide 13 is set.In epitaxial growth device 14, Ga metal, metal A l, the GaAs polycrystalline and being used to of suitable batching that sets gradually four epitaxially grown layers 2,3,4,5 of the Fig. 1 that is used to grow realized four crucibles 15~18 of the suitable batching of the conductivity type of each epitaxially grown layer and carrier concentration.
At first, the epitaxial growth device 14 of structure as shown in Figure 2 is arranged in the crystal reaction tube (not shown), in hydrogen stream, heats, the fusion raw material.Then, slide 13 is pressed against the right side, and the following and melt that p type GaAs substrate 11 moves to crucible 15 contacts.Then, cooling atmosphere temperature, a growth p type GaAlAs layer 2 shown in Figure 1 on p type GaAs substrate.Below, equally by carrying out the mobile and cooling of slide, the four layer epitaxially grown layers corresponding of growing repeatedly with Fig. 1.
As the means that reduce sulphur concentration and Ge concentration in the n type coating layer 5, in slip boat anchor clamps shown in Figure 2, with vitreous carbon coated substrates pack into the inboard of groove 12 and the inboard of crucible 15~18.The 20th, the part that expression applies with vitreous carbon.In addition, by with the direct part of contact Ga solution of vitreous carbon coating, it is poor to make with the wettability of Ga solution, in epitaxial process, can prevent to comprise the Ga solution that the p type active layer of Ge grows and sneak in the Ga solution of n type layer growth.
And, make crucible cover 19 by vitreous carbon.This crucible cover is used for preventing that the solution in crucible from sneaking into the purpose from other crucible steam, but also by made this crucible cover 19 by the vitreous carbon of low porosity, can prevent sneaking into of impurity etc.
In the past, sulphur concentration in the n type epitaxially grown layer and Ge concentration were about 5 * 10 respectively
16m
-3More than, but, sulphur concentration in the n type epitaxially grown layer and Ge concentration can be controlled at 3 * 10 by implementing said method
16Cm
-3Below.And, utilize this method, by the sulphur concentration in the n type epitaxially grown layer, Ge concentration are controlled at 3 * 10
16Cm
-3Below, compared with the past, can improve the high speed of DH structure and the output of high output infrarede emitting diode.
In addition, in this film build method, for make from the interface of a described p type layer 2 and p type coating layer 3 p type coating layer side 2 μ m with the maximum of silicon concentration the interior zone control less than 1 * 10
18Atom/cm
3, less than 4 * 10
17Atom/cm
3Better, best less than 1 * 10
17Atom/cm
3, the cooling rate when reducing the epitaxial growth of this part can make the unsteadiness of melt saturation reduce thus.Therefore, can reduce the silicon segregation of interface portion.In addition, the crucible cover 19 of making Fig. 2 by the low vitreous carbon of porosity also is effective.This is because quartzy system reaction tube by hydrogen reduction, produces low silica and silicon, but by reducing the porosity of crucible cover, can reduce these silicon sources and sneak in melt.
In addition, in order to control the concentration less than 1 * 10 of the carbon, sulphur and the oxygen that comprise in the described p type layer 2
17Atom/cm
3, the sky of device for carrying out said burns, so that prevent that sulfur oxide, carbonic acid gas are adsorbed on the slip boat parts when substrate, raw material are set, in addition, in slip boat anchor clamps, is effective with pack into the inboard of groove 12 and the inboard of crucible 15~18 of vitreous carbon coated substrates.
After above epitaxial growth finishes, take out epitaxial wafer, carry out elementization.Elementization is the surface with the n type GaAlAs layer 5 of acidproof protection Fig. 1, is that corrosive agent is removed the GaAs substrate selectively with ammonia-hydrogen peroxide.Then, on two surfaces of epitaxial wafer, form gold electrode, separate, make LED by scribing.
Because the infrared LED that obtains according to the present invention is high output, utilizes the transmission light-emitting component that uses in ultrared optical communication apparatus and the space conveyer so can be particularly useful as.In adorn infrared LED of the present invention optical communication apparatus, space conveyer be fit to that Large Volume Data is carried, long-range data transmits.
Below, utilize embodiment and comparative example to illustrate in greater detail the present invention, but the present invention is not limited to these
Embodiment.
Embodiment 1
Epitaxial growth utilizes slip boat shown in Figure 2 to be undertaken by liquid-phase growth method.In crucible 1518, Ga metal, metal A l, GaAs polycrystalline and the conduct of adding the batching that is suitable for each layer epitaxially grown realize the conductivity type of each epitaxially grown layer and the suitable alloy of carrier concentration, in the crucible 16 of the crucible 15 of a p type layer growth and p type coating layer, add Zn, in the crucible 17 of p type active layer growth usefulness, add Ge, in the crucible 18 of n type coating layer growth usefulness, add Te.
In slip boat anchor clamps, for the impurity that makes the carbon, sulphur, oxygen and the Ge that enter epitaxially grown layer reduces, with vitreous carbon 20 coated substrates pack into the inboard of groove 7 and the inboard of crucible 15~18.In addition, crucible cover 19 is made by the low vitreous carbon of porosity, so that do not sneak into the silicon of crystal reaction tube.
In addition, epitaxial growth device carries out 1 hour empty burning under about 1400 ℃ in hydrogen chloride gas atmosphere before implementing epitaxial growth.
And the corrosion treatment to the GaAs single crystalline substrate used in the epitaxial growth and GaAs polycrystalline use the high-purity corrosive agent then, utilizes pure water to carry out ultrasonic waves for cleaning and handles.In addition, the atmosphere gas such as argon that form the no hydrogen of epitaxial growth atmosphere use the gas that the high-pure gas of market sale is further purified with purifying plant.
Actual following the carrying out of epitaxial growth.The epitaxial growth device 14 of Fig. 2 is arranged in the crystal reaction tube, in hydrogen stream, is heated to 950 ℃, the fusion raw material.Then, make atmosphere temperature be cooled to 920 ℃, slide 13 is pressed against the right side, and the following and melt that makes p type GaAs substrate 6 move to crucible 10 contacts.Then, by speed 0.5 ℃/minute the speed cooling atmosphere temperature then that initial 10 minutes was 0.2 ℃/minute, a growth p type GaAlAs layer shown in Figure 1 on p type GaAs substrate.Below, equally by carrying out the mobile and cooling of slide, four layer the epitaxially grown layer that ratio of components different corresponding of growing repeatedly with Fig. 1.At this moment, the same under the situation of the epitaxially grown layer beyond the growing p-type active layer with the situation of lamination the one p type GaAlAs layer, by initial 10 minutes be 0.2 ℃/minute speed then 0.5 ℃/minute speed lower the temperature.
By adopting such cooling pattern, relax sharply separating out of epitaxially grown layer near interface, avoid the silicon of high concentration and separate out.For p type active layer, the growth temperature amplitude is 2 ℃, by whole area 0 .2 ℃ of/minute cooling.
Carry out several times intermittently film forming by above film build method.At this moment, make in the crucible 15~18 Ga metal, metal A l, the GaAs polycrystalline of batching, the amount of alloy carry out some variations within the scope of the invention.
After epitaxial growth finishes, measure ratio of components, carrier concentration and the thickness of each layer.It is Ga that its final ratio of components becomes a p type layer
1-x1Al
X1As (0.13≤X1≤0.40), p type coating layer is Ga
1-x2Al
X2As (0.23≤X2≤0.45), p type active layer is Ga
1-x3Al
X3As (X3=0.01), n type coating layer is Ga
1-x4Al
X4As (0.14≤X4≤0.40).There is the reason of scope to be in each layer ratio of components, because each layer is by the growth of slow cooling method, so the Al composition ratio of the epitaxially grown layer beyond the p type active layer reduces to the element surface side.In addition, carrier concentration is that a p type layer is 1 * 10 by the mean value of each layer
18Cm
-3, p type coating layer is 5 * 10
17Cm
-3, p type active layer is 2 * 10
18Cm
-3, n type coating layer is 1 * 10
17~1 * 10
18Cm
-3, the thickness of each layer is that a p type layer is 80 μ m, and p type coating layer is 70 μ m, and p type active layer is 0.5 μ m, and n type coating layer is 40 μ m.
Use this epitaxial wafer to make element.At first, with the surface of the n type GaAlAs layer 5 of acidproof thin slice protection Fig. 1, be that corrosive agent is removed GaAs substrate 1 selectively with ammonia-hydrogen peroxide.Then, after peeling off acidproof thin slice, on epitaxial wafer two-sided, form gold electrode, come resolution element, make infrared LED by scribing.
The growth from epitaxially grown layer of the speed of growth of each epitaxially grown layer is begun to finishing all to be set at 1.0 ℃/minute, and other condition is identical with embodiment 1, implements epitaxial growth, making LED.
The growth from epitaxially grown layer of the speed of growth of each epitaxially grown layer is begun to finishing all to be set at 0.6 ℃/minute, and other condition is identical with embodiment 1, implements epitaxial growth, making LED.
Comparative example 1
The cooling rate of the atmosphere temperature when making each epitaxial growth layer growth is all 1.0 ℃/minute mutually with embodiment 1, and the material of the crucible cover 19 of above-mentioned Fig. 2 is changed to common graphite from vitreous carbon, and other condition is identical with embodiment 1, makes LED.
Fig. 3 is illustrated in carrier concentration, the sulphur concentration in the n type coating layer and the result of luminous output who measures n type coating layer among the LED that embodiment 1 (■ symbol), comparative example (symbol) make.The numeric representation relative luminous intensity.As seen from the figure, be controlled at 1 * 10 by carrier concentration with n type coating layer
17Cm
-3More than 1 * 10
18Cm
-3Below, the sulphur concentration of n type coating layer is controlled at 3 * 10
16Cm
-3Below, can make the high LED of luminous relatively output.
Fig. 4 is the result who measures the silicon concentration of a p type GaAlAs and p type coating layer near interface in the sample of embodiment 1~3 and comparative example 1.As known in the figure, enter the peak value that p type coating layer only has silicon concentration in the zone of 2 μ m from the interface of a p type GaAlAs and p type coating layer.According to the result of embodiment 1 and embodiment 2, the speed of growth that begins part in epitaxial growth is under 0.5 ℃/minute the situation, compares with 0.2 ℃/minute situation, and the silicon peak concentration uprises, if the speed of growth reaches 1.0 ℃/minute, the silicon peak concentration is higher.In addition, according to the result of embodiment 3 and comparative example 1, even the identical speed of growth if the material of described crucible cover 19 becomes graphite from vitreous carbon, can judge that so the silicon peak concentration uprises.
In addition, Fig. 5 is illustrated in the silicon peak concentration of near interface of above-mentioned p type GaAlAs layer and p type coating layer and the curve chart of LED output relation.As known in the figure, if the silicon concentration peak value of near interface surpasses 1 * 10
18Atom/cm
3, LED output descends so, and the deviation of output increases simultaneously.In addition, by making silicon concentration peak value less than 1 * 10
18Atom/cm
3, 4 * 10
17Atom/cm
3Below better, best less than 1 * 10
17Atom/cm
3, can obtain the height output of the little LED of deviation.
According to above result, in order to reduce the silicon temperature of near interface, reducing the speed of growth and crucible cover is that vitreous carbon is effective.But under the situation that reduces the speed of growth, owing to there is the time lengthening of epitaxial growth technology needs, the problem that productivity ratio descends is effective so only reduce the speed of growth near interface.
Fig. 6, Fig. 7, Fig. 8 represent the relation of carbon, sulphur and the oxygen concentration in the p type GaAlAs layer and LED output in embodiment 1 and the comparative example 1 respectively.Among the figure, ◆ symbol is the LED output of embodiment 1, and the ◇ symbol is the LED output of comparative example 1.As shown in Figure 6, by making the concentration of carbon less than 1 * 10 in the p type GaAlAs layer
17Atom/cm
3, can obtain the LED output of practical grade relative intensity.In addition, by Fig. 7, Fig. 8 as can be known, for sulphur, oxygen concentration, also by making the concentration less than 1 * 10 in the p type GaAlAs layer
17Atom/cm
3, can obtain the LED output of practical grade relative intensity.As described above,, make crucible cover 19, carbon, sulphur and oxygen concentration in the epitaxially grown layer are reduced, LED output is improved with vitreous carbon by apply substrate shown in Figure 2 pack into groove 12 and crucible 15~18 with vitreous carbon.
Fig. 9 represents the Ge concentration in the n type coating layer of the light-emitting diode that obtained by embodiment 1 (◆ symbol) and comparative example 1 (◇ symbol) and the relation of luminous output.
As shown in Figure 9, as can be known the Ge concentration in the n type coating layer 1 * 10
16Cm
-3When following output basicly stable, if but become than 1 * 10
16Cm
-3Height, output begins to descend so.And, if Ge concentration becomes than 3 * 10
16Cm
-3Height, output sharply descends so.Therefore, obviously utilize Ge concentration in the n type coating layer 3 * 10
16Cm
-3Below, 1 * 10
16Cm
-3Better, just can reach high output.
As shown in the above description, in the epitaxial wafer that the GaAlAs of DDH structure of the present invention infrared LED is used, if the carrier concentration of n type coating layer is 1 * 10
17~1 * 10
18Cm
-3, sulphur concentration is 3 * 10
16Atom/cm
3Below, layer thickness is 20~50 μ m, can make the epitaxial wafer that can make high output LED so.
Especially begin the silicon concentration maximum less than 1 * 10 of part by the growth that makes p type coating layer
18Atom/cm
3, the concentration less than 1 * 10 of carbon, sulphur and oxygen in the p type GaAlAs layer
17Atom/cm
3, the Ge concentration in the n type coating layer is 3 * 10
16Atom/cm
3Below, just can make the little epitaxial wafer of the high deviation of output.
In addition, in the epitaxial wafer of this structure, the thickness by making p type coating layer can be made the higher epitaxial wafer of output in the scope of 50~80 μ m.
And the carrier concentration by making a p type GaAlAs layer is 3 * 10
17~1 * 10
18Cm
-3Scope in, can provide to make VF reduce the higher epitaxial wafer of output.
Epitaxial wafer of the present invention is by especially setting the cooling rate of the atmosphere temperature at p type coating layer film forming initial stage to such an extent that be lower than the cooling rate in p type coating layer film forming later stage, can boost productivity, and can reduce the silicon concentration of p type coating layer near interface, can make the epitaxial wafer of the little infrared LED of the high deviation of exporting.
In addition, utilize the epitaxial wafer of infrared LED of the present invention, can reach the high luminous output of infrared LED, can offer with Large Volume Data transmission, long-range data and transmit corresponding optical communication apparatus, space conveyer etc.
Claims (7)
1. the epitaxial wafer that infrarede emitting diode is used ends with liquid phase epitaxial process sequential laminating the one p type layer Ga in p type GaAs single crystalline substrate
1-x1Al
X1As, p type coating layer Ga
1-x2Al
X2As, the emission wavelength p type active layer Ga in 850~900nm scope
1-x3Al
X3As and n type coating layer Ga
1-x4Al
X4Behind the As, remove this p type GaAs single crystalline substrate, wherein, 0.13≤X1≤0.40,0.23≤X2≤0.46,0≤X3≤0.03,0.13≤X4≤0.40 is characterized in that, the carrier concentration of n type coating layer is 1 * 10
17~1 * 10
18Cm
-3In the scope, and sulphur concentration is 3 * 10
16Atom/cm
3Below.
2. the epitaxial wafer that infrarede emitting diode as claimed in claim 1 is used is characterized in that, the layer thickness of this n type coating layer is in the scope of 20~50 μ m.
3. the epitaxial wafer of using as the infrarede emitting diode of claim 1 or 2 is characterized in that, from the interface of this a p type coating layer and a p type layer to the maximum less than 1 * 10 of p type coating layer side 2 μ m with silicon concentration the interior zone
18Atom/cm
3
4. the epitaxial wafer of using as the infrarede emitting diode of claim 1 or 2 is characterized in that, the concentration less than 1 * 10 of carbon, sulphur and oxygen in the p type layer
17Atom/cm
3
5. the epitaxial wafer of using as the infrarede emitting diode of claim 1 or 2 is characterized in that, the layer thickness of this p type coating layer is in the scope of 50~80 μ m.
6. the epitaxial wafer of using as the infrarede emitting diode of claim 1 or 2 is characterized in that, the carrier concentration of a p type layer is 3 * 10
17Cm
-3~1 * 10
18Cm
-3Scope in.
7. the epitaxial wafer of using as the infrarede emitting diode of claim 1 or 2 is characterized in that, the major impurity of this p type active layer is a germanium, and the Ge concentration in the n type coating layer is 3 * 10
16Atom/cm
3Below.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11968999A JP2000312026A (en) | 1999-04-27 | 1999-04-27 | Epitaxial substrate for infrared light-emitting element and light-emitting element using the same |
JP119689/1999 | 1999-04-27 | ||
JP26648399A JP4402217B2 (en) | 1999-09-21 | 1999-09-21 | Epitaxial substrate for infrared light emitting device and light emitting device produced using the same |
JP266483/1999 | 1999-09-21 |
Publications (2)
Publication Number | Publication Date |
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CN1273438A CN1273438A (en) | 2000-11-15 |
CN1160803C true CN1160803C (en) | 2004-08-04 |
Family
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CNB001182943A Expired - Lifetime CN1160803C (en) | 1999-04-27 | 2000-04-27 | Epitaxial growth chip used for infrared emitting diode and infrared emitting diode |
Country Status (3)
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CN (1) | CN1160803C (en) |
DE (1) | DE10020501B4 (en) |
TW (1) | TW498560B (en) |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3902454A (en) * | 1968-09-27 | 1975-09-02 | Matsushita Electric Ind Co Ltd | Apparatus for epitaxial growth from the liquid state |
DE3605973A1 (en) * | 1986-02-25 | 1987-08-27 | Licentia Gmbh | Liquid-phase epitaxial arrangement |
JPH0639356B2 (en) * | 1986-05-16 | 1994-05-25 | イビデン株式会社 | Boat member for liquid phase epitaxial growth equipment |
US4912532A (en) * | 1988-08-26 | 1990-03-27 | Hewlett-Packard Company | Electro-optical device with inverted transparent substrate and method for making same |
JP3356041B2 (en) * | 1997-02-17 | 2002-12-09 | 昭和電工株式会社 | Gallium phosphide green light emitting device |
-
2000
- 2000-04-25 TW TW89107735A patent/TW498560B/en not_active IP Right Cessation
- 2000-04-26 DE DE2000120501 patent/DE10020501B4/en not_active Expired - Lifetime
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TW498560B (en) | 2002-08-11 |
CN1273438A (en) | 2000-11-15 |
DE10020501A1 (en) | 2001-04-05 |
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