JP4961820B2 - Method for producing compound semiconductor - Google Patents

Description

The present invention relates to a compound semiconductor manufacturing how relates particularly high quality nitrogenous compound semiconductor manufacturing how.

  The III-V group compound semiconductor has a large band gap and a direct transition type between band transitions, so that development to a light emitting element and an electronic element is greatly expected. When growing a group III-V compound semiconductor crystal by a metal organic chemical vapor deposition (MOCVD) method, a group III material for supplying a group III element and a group V material for supplying a group V element are used.

For example, triethyl gallium (TEGa) and trimethylindium (TMI) organic group III material, such as (M1), dimethyl hydrazine (DMHy), organic nitrogen compounds such as monomethyl hydrazine (MMHy) and (M2), arsine (AsH ₃ ), Organic arsenic compounds such as tertiary butylarsine (TBA) and trimethylarsenic, organic V group materials (M3) such as organic phosphorus compounds such as phosphine (PH ₃ ) and tertiary butylphosphine (TBP), and hydrogen A method of vapor phase growth using a carrier gas as a carrier gas is known (for example, see Patent Documents 1 and 2).
JP-A-11-340577 Japanese Patent Application Laid-Open No. 11-238685

  However, when an organic nitrogen compound such as DMHy is used as a raw material, a defect called a dangling bond occurs. When a dangling bond is generated, a semiconductor laser having GaInNAs as an active layer causes problems such as a high threshold.

The occurrence of such dangling bonds is considered to occur as follows. For example, DMHy has a structure represented by the following chemical formula.

  When DMHy is decomposed and nitrogen is taken into the crystal, a portion surrounded by a circle of the above chemical formula is taken in. That is, since the N—H bond is stable, the N—H bond is not broken and is taken into the crystal. For this reason, group III elements such as Ga and In which should originally be bonded to N cannot be bonded to N, resulting in dangling bonds. As described above, the phenomenon that the N—H bond is taken into the crystal is that (1) the GaInAs crystal containing no nitrogen contains almost no hydrogen, and (2) the N concentration in the GaInNAs crystal increases as the N concentration increases. This is confirmed by the increase in hydrogen concentration.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a compound semiconductor capable of obtaining a compound semiconductor crystal of good crystal quality and a vapor phase growth apparatus for manufacturing the compound semiconductor. is there.

To achieve the above object, a manufacturing method of a compound semiconductor of the present invention, in the reaction tube, and a nitrogen raw material, a group V material other than at least one of the nitrogen source, by using a group III material, the susceptor A method for producing a compound semiconductor by vapor-phase-growing a group III-V compound semiconductor containing nitrogen on a placed group III-V compound semiconductor substrate, wherein the nitrogen source is hydrazine, monomethylhydrazine, 1,1-dimethylhydrazine , And at least one selected from 1,2-dimethylhydrazine, the Group V raw material includes a Group V chloride, and the Group V chloride is selected from arsenic trichloride, phosphorus trichloride, and antimony trichloride. The group V raw material containing at least one group and containing the group V chloride and the nitrogen raw material are mixed immediately on the group III-V compound semiconductor substrate.

In the method of the present invention, the group V raw material, containing chlorides of Group V element other than nitrogen such as arsenic trichloride or phosphorus trichloride. When arsenic trichloride or phosphorus trichloride is thermally decomposed, chlorine ions are generated. As shown in the following chemical formula, this chlorine ion reacts with the organic nitrogen compound (X—NH ₂ ) to break the N—H bond in the molecule of the nitrogen raw material.

A method for producing a compound semiconductor according to the present invention includes a group III-V using a nitrogen source such as hydrazine , a group V source other than at least one nitrogen source including a group V chloride, and a group III source. the group III-V compound semiconductor containing nitrogen compound semiconductor substrate Ru der which vapor phase growth.

  The group V raw material containing chloride is a liquid and can be stably supplied by bubbling or the like.

H contained in the nitrogen raw material is discharged as hydrogen chloride (HCl) (X is also discharged), and only nitrogen is taken into the crystal. As a result, since the group III element and nitrogen can be bonded, generation of dangling bonds can be prevented. The use of group V chloride in this way is that chlorine ions are excellent in reactivity with hydrogen in the N—H bond, and chlorine has a sufficiently large atomic radius compared to hydrogen, so it is temporarily incorporated into the semiconductor crystal. But it is not as bad as hydrogen.

The nitrogen source is at least one selected from hydrazine, monomethyl hydrazine, 1,1-dimethyl hydrazine, and 1,2-dimethyl hydrazine. Group V chlorides include arsenic trichloride, phosphorus trichloride, and Ru least Tanedea selected from antimony chloride. Chlorine ions generated from the Group V chloride in the Group V material break the NH bond in the molecule of the nitrogen material, so that Group III elements such as Ga and In are combined with N in the crystal, and dangling. Bond does not occur.

The group V raw material and the nitrogen raw material containing V group chloride, Ru is mixed with III-V compound semiconductor substrate on the most recent. HCl gas generated by the reaction between the group V chloride and the nitrogen source has an etching action. For this reason, if a V group raw material containing a V group chloride and a nitrogen raw material are mixed at an early stage, HCl gas is generated, and an already grown semiconductor crystal is etched. If a group V raw material containing a group V chloride and a nitrogen source are mixed in the immediate vicinity of the compound semiconductor, the generated HCl gas will be exhausted before performing the etching action. As a result, it is possible to prevent the generated HCl gas from etching the already grown semiconductor crystal.
In order to mix the group V raw material containing the group V chloride and the nitrogen raw material immediately on the group III-V compound semiconductor substrate, a supply path for the group V raw material containing the group V chloride or the nitrogen source is provided in the reaction tube. Preferably it extends over the susceptor.

  The carrier gas for supplying the raw material is preferably an inert gas not containing hydrogen. When a carrier gas containing hydrogen is used, the hydrogen in the carrier gas hinders the reaction between chlorine ions generated from chloride and hydrogen contained in the nitrogen raw material. Therefore, by using an inert gas that does not contain hydrogen, it is possible to more efficiently remove hydrogen from the nitrogen source.

A vapor phase growth apparatus cited as a reference example of the present invention includes a reaction tube for growing a semiconductor on a substrate, a susceptor disposed in the reaction tube for mounting the substrate, and communicating with the reaction tube. A first source gas supply unit to which at least two types of source gases are supplied, and a second source gas supply unit that extends to the susceptor and supplies another source gas in the reaction tube. If it is.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the compound semiconductor which can obtain the compound semiconductor crystal of favorable crystal quality with few dangling bonds by effectively removing the hydrogen contained in a nitrogen raw material, and the gaseous phase which manufactures it A growth apparatus can be provided.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  In the present embodiment, a case where GaInNAs is grown as a group III-V compound semiconductor will be described as an example.

[Manufacturing equipment]
The MOCVD (Metal Organic Chemical Vapor Deposition) apparatus applied to the GaInNAs crystal growth method according to the present embodiment will be described below. FIG. 1 is a diagram schematically showing an MOCVD apparatus.

As shown in FIG. 1, a vapor phase growth apparatus 1 cited as a reference example of the present invention is arranged in a reaction tube 2 for growing a semiconductor on a substrate, and in the reaction tube 2, and mounts the substrate. A susceptor 3, a source gas supply port (first source gas supply unit) 4 to which at least two kinds of source gases are supplied, and the reaction tube 2, which extends above the susceptor 2, 2 has a supply path (second source gas supply unit) 5 having a supply port 6 for supplying source gas, and an exhaust pipe 7 for exhausting the source gas. With this structure, the group V raw material containing the group V chloride and the nitrogen source can be mixed in the immediate vicinity of the group III-V compound semiconductor substrate. “Mixing in the immediate vicinity of the substrate” means mixing so that the HCl gas generated by the mixing is easily exhausted by the exhaust gas flowing on the substrate. For example, the supply port for the group V raw material containing group V chloride and / or the supply port for the nitrogen material is located several mm to several centimeters upstream from the substrate end, and the above material is continuously and smoothly supplied to the back surface of the substrate. It refers to the position where it can be supplied (see FIG. 1). A heating device for controlling the temperature of the substrate provided in the reaction tube may be provided around the reaction tube 2. In FIG. 1, “Group V source gas” is a simplified form of “Group V source gas including group V chloride”.

  Examples of the gallium raw material include trimethyl gallium (TMGa) and triethyl gallium (TEGa).

  Examples of indium raw materials include trimethylindium (TMIn) and triethylindium (TEIn).

  Examples of the nitrogen raw material include hydrazine, monomethyl hydrazine, 1,1-dimethyl hydrazine, and 1,2-dimethyl hydrazine.

  Examples of the arsenic raw material include arsine and tertiary butylarsine (TBA).

  Each of the raw materials is stored in a raw material cylinder (not shown) and supplied to the reaction vessel 2 from the raw material gas supply port 4 as a mixed gas together with a carrier gas.

Examples of raw materials containing chlorine include Group V chloride materials such as arsenic trichloride, phosphorus trichloride, and antimony trichloride, and Group III chloride materials such as indium trichloride and gallium trichloride as reference examples. .

  The group V chloride raw material is stored in a raw material cylinder (not shown), and is supplied to the reaction vessel 2 from the supply path 5 as a mixed gas together with the carrier gas. The raw material supplied to the reaction tank 2 from the supply path 5 may be a group V chloride raw material alone or a mixture with another group V raw material that does not react with the group V chloride raw material.

[Method of forming GaInNAs layer]
The source gas is introduced into the reaction vessel 2 from the source gas supply port 4 together with the carrier gas. In addition, during the crystal growth of GaInNAs, the group V source gas containing group V chloride is introduced into the reaction vessel 2 from the supply port 6 through the supply path 5 together with the carrier gas. Each raw material is thermally decomposed in the reaction vessel 2 and deposited on a substrate (for example, a GaAs substrate) to form a GaInNAs layer. During the pyrolysis reaction, Group V chlorides Group V in the feed Cl ions which occurs by thermal decomposition, by cutting the N-H bond of the nitrogen source, HCl gas is generated. The composition ratio of the GaInNAs is _generally expressed by _{Ga 1-x In x N y} As 1-y.

The group V source material containing V group chloride, in combination with V group chloride, and other group V raw material to supply the same V group element T BA like a V ZokuHara fees other than nitrogen. The composition of N in the GaInNAs composition is about several to 10%, which is 1/10 or less of the As composition. Since the concentration of hydrogen taken into GaInNAs is about one-tenth of the N composition, arsenic trichloride can be sufficiently removed if it is about a fraction of the TBA concentration. On the other hand, if the concentration of arsenic trichloride is high, the generated chlorine ions have an adverse effect. For this reason, arsenic trichloride is preferably used in combination with other Group V materials such as TBA.

During the crystal growth of GaInNAs, the flow rate of the Group V (N, As) material relative to the flow rate of the Group III (Ga, In) material in the supplied material can be several times to several hundred times, for example. The flow rate of the nitride material (DMHy or MMHy) relative to the flow rate of the arsenic material (AsH ₃ or TBA ) can be several tens to several hundreds times. The substrate temperature during the crystal growth of GaInNAs can be set to 400 to 700 ° C., for example. Moreover, the pressure in the reaction tank 2 can be made into about 5.33 to 101.33 kPa, for example. Moreover, you may provide the control means which controls the flow volume of each raw material into the reaction tank 2.

In the above description, the crystal growth of GaInNAs has been described as an example, but the III-V group compound containing N is not limited to GaInNAs, and may be GaNAs, GaNP, GaInNAsSb, or GaInNAsP. For example, in the case of crystal growth of GNP, phosphine (PH ₃ ) or tertiary butyl phosphine (TBP) may be used as a phosphorus raw material, and phosphorus trichloride may be used as a phosphorus chloride raw material.

Example 1
As shown in FIG. 2, a GaAs layer 12 (film thickness 0.2 μm), a GaInNAs layer 13 (film thickness 8 nm), and a GaAs layer 14 (film thickness 14 nm) are formed on the (100) plane of a GaAs substrate 11 doped with 350 μm thick silicon. A film thickness of 0.1 μm) was sequentially formed.

The growth method of the GaInNAs layer 13 was performed by the MOCVD method using the apparatus shown in FIG. TMIn, TMG, DMHy, TBA, and arsenic trichloride were used as raw materials. N ₂ was used as a carrier gas.

  These raw materials and nitrogen gas are supplied onto the GaAs substrate 11 placed on the heated susceptor 3 in the reaction vessel 2 for growth. Arsenic trichloride was supplied onto the substrate via the supply path 5. The supply amount of arsenic trichloride was about 1/10 to 1/5 of TBA. In Example 1, the GaInNAs layer 13 was grown at 510 ° C., a growth pressure of 10.133 kPa, and a growth rate of 1 μm / hour. The crystal composition of GaInNAs is Ga: 66%, In: 34%, N: 1%, As: 99%.

(Comparative Example 1)
Only TBA was used as an arsenic raw material without using arsenic trichloride. Further, hydrogen was used as a carrier gas. The other raw materials and conditions such as the growth temperature of GaInNAs were the same as in the example, and the semiconductor multilayer structure of FIG. 2 was created.

(Measurement result of photoluminescence intensity)
In Example 1 and Comparative Example 1, after the GaInNAs layer was grown, annealing treatment was performed at 670 ° C. for 10 minutes in a TBA atmosphere in order to increase the photoluminescence intensity. Before and after the annealing treatment, the light emission intensity increased by an order of magnitude or more in the laminated structure of Comparative Example 1. On the other hand, in the laminated structure of Example 1, the emission intensity was about five times stronger than that of Comparative Example 1. The light emission intensity after the annealing treatment was 5 to 10 times stronger in the laminated structure of Example 1 than in the laminated structure of Comparative Example 1.

(Measurement result of hydrogen concentration)
When the hydrogen concentration in the GaInNAs layer in the obtained semiconductor multilayer structure was measured using a secondary ion mass spectrometer (SIMS), it was 1 × 10 ¹⁸ cm ⁻³ in Example 1, and in Comparative Example 1, 1 × 10 ¹⁹ cm ⁻³ .

Note that when InGaNSbAs (crystal composition is Ga: 50%, In: 50%, N: 2%, Sb: 5%, As: 93%) is grown on the InP substrate, the same as in Example 1 above. The effect was obtained. Therefore, _{In 1-x Ga} of GaAs substrate or InP substrates _{x N y Sb z As (1} -y-z-w) (1 ≧ x ≧ 0,0.2 ≧ y> 0,0.2 ≧ It can be seen that this is also effective when z ≧ 0, 0.1 ≧ w ≧ 0).

From this result, it was found that the removal of hydrogen can be effectively performed by containing a group V chloride as a group V raw material.

  Although the embodiments and examples of the present invention have been described above, the embodiments and examples of the present invention disclosed above are merely examples, and the scope of the present invention is the implementation of these inventions. It is not limited to the form. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

FIG. 1 is a diagram schematically showing an MOCVD apparatus. FIG. 2 is a diagram showing a semiconductor stacked structure.

DESCRIPTION OF SYMBOLS 1 Vapor growth apparatus, 2 Reaction tube, 3 Susceptor, 4 Source gas supply port (1st source gas supply part), 5 Supply path (2nd source gas supply part), 6 Supply port (2nd source gas) Supply section), 7 exhaust pipe, 11 Si-doped GaAs substrate, 12 GaAs layer, 13 GaInNAs layer, 14 GaAs layer.

Claims (3)

III-V containing nitrogen on a III-V group compound semiconductor substrate placed on a susceptor using a nitrogen source, a group V source other than at least one nitrogen source, and a group III source in a reaction tube A compound semiconductor manufacturing method for vapor-phase-growing a group compound semiconductor,
The nitrogen raw material is at least one selected from hydrazine, monomethylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine, and the group V raw material includes a group V chloride, and the group V chloride The product is at least one selected from arsenic trichloride, phosphorus trichloride, and antimony trichloride,
The method for producing a compound semiconductor, wherein the group V raw material containing the group V chloride and the nitrogen source are mixed immediately on the group III-V compound semiconductor substrate. 2. The method for producing a compound semiconductor according to claim 1, wherein in the reaction tube, a supply path for a group V source material or nitrogen source containing the group V chloride is extended to above the susceptor . 3. The method for producing a compound semiconductor according to claim 1, wherein a carrier gas for supplying the group V source and the group III source is an inert gas not containing hydrogen. 4.