JP5183904B2 - Semiconductor manufacturing method - Google Patents

Description

  The present invention relates to a semiconductor manufacturing method in which a semiconductor composed of three or more constituent elements including nitrogen is grown on a substrate by a vapor phase growth method.

  In general, nitrogen is known to have a large dissociation energy and low efficiency of incorporation into a crystal, so that it is difficult to grow a single crystal only by supplying it onto a substrate. On the other hand, when a semiconductor containing nitrogen as a constituent element is grown on a substrate by a vapor deposition method, a reactive nitrogen gas obtained by activating a nitrogen gas as a nitrogen source by a high-frequency plasma is introduced onto the substrate. There is a technique for crystal growth (see, for example, Patent Document 1).

JP-A-6-37355 Japanese Patent No. 3735047 T. Kageyama et al., J. Cryst. Growth, 2000, p. 350-354 T. Honda et al., J. Cryst. Growth, 2002, p. 1008-1011 T. Honda et al., J. Vac. Sci. Technol. B, 2004, Vol. 22, No. 4, p. 2155-2157 H. Shimizu et al., IEEE J. Select. Topics Quantum Electron., 2001, Vol. 7, p. 355-364

  However, when a semiconductor is crystal-grown using a reactive nitrogen gas activated by high-frequency plasma as described above, the crystal quality deteriorates due to the influence of radicals and the like generated by the plasma excitation of the nitrogen gas. (For example, refer nonpatent literature 1).

  This invention is made | formed in view of the above, Comprising: It aims at providing the manufacturing method of the semiconductor which can grow the semiconductor which has high crystal quality.

In order to solve the above-described problems and achieve the object, a semiconductor manufacturing method according to the present invention is a semiconductor manufacturing method in which a semiconductor composed of three or more constituent elements containing nitrogen is grown on a substrate by vapor deposition. A nitride gas generating step for generating a nitride gas based on a nitride material containing nitrogen, and a non-nitride material having an element not included in the nitride material among the constituent elements of the semiconductor A non-nitride gas generating step for generating a non-nitride gas, and a semiconductor growth step for growing the semiconductor by introducing and combining the nitride gas and the non-nitride gas onto the substrate. It is characterized by that.

Further, in the semiconductor manufacturing method according to the present invention , in the above invention, an auxiliary gas generation step of generating an auxiliary material gas based on an auxiliary material containing an element other than nitrogen among elements contained in the nitride material. The semiconductor growth step is characterized in that the nitride gas, the non-nitride gas, and the auxiliary source gas are introduced and combined on the substrate to grow the semiconductor.

The semiconductor manufacturing method according to the present invention is characterized in that, in the above invention, the nitride gas generation step generates the nitride gas and the non-nitride gas based on the nitride raw material. To do.

Further, in the semiconductor manufacturing method according to the present invention , in the above invention, an element other than nitrogen contained in the nitride material is a group III element, and among the constituent elements of the semiconductor, the element is contained in the nitride material. The element which is not is characterized by being at least one of a group V element and a group III element.

The semiconductor manufacturing method according to the present invention is characterized in that, in the above invention, the nitride material is GaN.

Further, the semiconductor manufacturing method according to the present invention includes a reactive nitrogen gas generation step of generating a reactive nitrogen gas by activating the nitrogen gas with plasma in the above invention, wherein the semiconductor growth step includes the nitride A gas, the non-nitride gas, and the reactive nitrogen gas are introduced onto the substrate and combined to grow the semiconductor.

The semiconductor manufacturing method according to the present invention is characterized in that, in the above invention, the semiconductor has a nitrogen composition ratio of less than 10%.

In the semiconductor manufacturing method according to the present invention as set forth in the invention described above, the nitride gas is a nitride molecular beam generated based on the nitride raw material.

  According to the semiconductor manufacturing method of the present invention, a semiconductor having high crystal quality can be grown.

  The semiconductor manufacturing method of the present invention is a method for growing a semiconductor containing nitrogen as a constituent element on a substrate by a vapor phase growth method, a nitride gas generated based on a nitride material, and a non-nitride A non-nitride gas generated based on a raw material is introduced onto a substrate to grow a semiconductor.

  The semiconductor manufacturing method of the present invention is suitable for a semiconductor manufacturing method by physical vapor deposition such as vacuum evaporation or sputtering. In particular, in order to grow a semiconductor having a predetermined composition ratio, it is preferable to use a semiconductor growth method by molecular beam epitaxy (MBE) as a physical vapor deposition method.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a semiconductor manufacturing method according to the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments.

(Embodiment)
FIG. 1 is a schematic diagram for explaining MBE as a method for manufacturing a semiconductor according to an embodiment of the present invention, and an MBE apparatus that realizes MBE in which GaNAs is grown on a substrate as an example of a semiconductor. The structure of 100 main parts is shown. As shown in this figure, the MBE apparatus 100 includes molecular beam generation units 3 to 5 that supply each constituent element of GaNAs2 to the substrate 1 by molecular beams in order to grow the GaNAs2 on the substrate 1. The substrate 1, the GANAS 2 and the molecular beam generators 3 to 5 are provided in an ultrahigh vacuum space defined by a vacuum chamber (not shown), and the substrate 1 is heated to a predetermined temperature by a heater or the like (not shown).

The molecular beam generation units 3 to 5 are realized by using, for example, a K cell (Knudsen Cell), generate molecular beams based on the raw materials held therein, and eject them toward the substrate 1. Specifically, the molecular beam generator 3 generates a molecular beam 6 that is a nitride molecular beam as a nitride gas based on the GaN powder 3a as a nitride raw material. As will be described later, the molecular beam 6 contains GaN, Ga, and N ₂ in a molecular state. The molecular beam generator 4 generates a molecular beam 7 as a non-nitride gas based on the non-nitride material 4a having As as an element not included in the GaN powder 3a among the constituent elements of GaNAs. 1 on top. The molecular beam generator 5 generates a molecular beam 8 as an auxiliary material gas based on the auxiliary material 5a containing Ga which is an element other than N among the elements contained in the GaN powder 3a. Introduce.

  In the MBE according to the present embodiment using such an MBE apparatus 100, as the nitride gas generation process, the molecular beam 6 as the nitride gas is generated based on the GaN powder 3a, and the non-nitride gas generation process is performed. The molecular beam 7 as the non-nitride gas is generated based on the non-nitride material 4a having As, and the molecular beam as the auxiliary material gas is generated based on the auxiliary material 5a containing Ga as an auxiliary gas generation step. As a semiconductor growth process, molecular beams 6 to 8 are introduced onto the substrate 1 and combined to grow GNAs2. Each of these steps is appropriately performed simultaneously or in accordance with a predetermined procedure.

  As a result, in the MBE according to the present embodiment, GaNAs 2 as a semiconductor can be grown on the substrate 1 without using reactive nitrogen gas activated by high-frequency plasma, and in particular, a semiconductor having a low nitrogen composition ratio. GaNAs (hereinafter referred to as a dilute nitrogen semiconductor) can be grown on the substrate 1. Here, the diluted nitrogen semiconductor means a semiconductor having a nitrogen composition ratio of less than 10%. However, it is not necessary to strictly interpret it as less than 10%, and even if the nitrogen composition ratio is slightly higher than 10%, the effect of the present invention is not limited.

Next, the operation of the MBE according to the present embodiment will be described in detail. First, Non-Patent Document 2 discloses a result of growing a GaN crystal by MBE (CS-MBE: Compound Source MBE) using GaN powder as a raw material. According to this, as a result of growing a GaN crystal on a 6H-SiC substrate using GaN powder of purity 5N (99.999%) as a raw material, a Ga-excess GaN crystal is obtained. Furthermore, from the analysis result of the surface composition by Auger electron spectroscopy (AES), it is explained that CS-MBE has a supply mechanism represented by the following formula (1).
GaN powder → (heating) → GaN + Ga + N ₂ (1)

Equation (1) indicates that a molecular beam using GaN powder as a raw material contains GaN, Ga, and N ₂ , and a part of this molecular beam reaches the substrate as a stable molecule of GaN. Further, since N ₂ does not contribute to the growth, the molecular beam substantially contains more Ga than N. From this, it is considered that a Ga-rich GaN crystal was grown in the result of the CS-MBE described above. In the MBE according to the present embodiment, a molecular beam 6 is supplied to the substrate 1 as a molecular beam having the characteristics shown in the formula (1).

Further, Non-Patent Document 3 discloses the experimental results shown in FIG. This result shows the N / Ga ratio in the GaN film when the GaN film is grown on the substrate using the GaN powder with respect to the substrate temperature during the growth. From this, it can be seen that, for example, when the substrate temperature is 450 ° C., N / Ga = 0.25. That is, the GaN film grown at a substrate temperature of 450 ° C. has a composition ratio of Ga: N = 4: 1, which confirms that this growth was an excess of Ga. When this result is applied to the decomposition process of the GaN powder shown in Formula (1) and considering that N ₂ is not involved in crystal growth, in the MBE according to the present embodiment, when the temperature of the substrate 1 is 450 ° C., It can be understood that GaN and Ga are present in the molecular beam 6 at a ratio of GaN: Ga = 1: 3.

Therefore, in the MBE according to the present embodiment, the molecular beam 6 containing GaN and Ga and the molecular beam 7 containing As are introduced together and combined on the substrate 1 at this ratio to grow GaNAs. GaNAs having a high nitrogen composition of GaN _0.25 As _0.75 can be generated. Further, in the MBE according to the present embodiment, the molecular beam 8 containing Ga is combined and introduced onto the substrate 1 and combined to grow GaNAs, thereby reducing the nitrogen composition ratio and reducing the concentration of the diluted nitrogen semiconductor. GaNAs is generated.

  By the way, when a semiconductor is grown, since N having a small atomic radius is difficult to combine with a V group atom such as As, the growth is usually performed in a non-equilibrium state at a low growth temperature. However, when the growth is performed at such a low temperature, there is a problem that crystal defects in the semiconductor are increased and optical characteristics are deteriorated (see, for example, Patent Document 2). On the other hand, in the MBE according to the present embodiment, as understood from the result shown in FIG. 2, the amount of nitrogen in GaNAs tends to increase as the temperature of the substrate 1 rises. By controlling the amount of Ga supplied by 8, a semiconductor having a desired nitrogen composition ratio, particularly a dilute nitrogen semiconductor, can be grown with high quality even in a high temperature state, and a dilute nitrogen semiconductor having excellent optical characteristics can be obtained. .

Next, the amount of Ga supplied by the molecular beam 8 will be described. Here, as a specific example, the growth of GaNAs having a nitrogen composition ratio of 2%, that is, GaN _0.02 As _0.98 is considered. The temperature of the substrate 1 is 450 ° C., and Ga and N are supplied by the molecular beam 6 at a ratio of N / Ga = 0.25. Further, all Ga supplied by the molecular beam 8 contributes to the growth of GaNAs, and As is supplied by the molecular beam 7 without any shortage.

In this case, the GaN powder 3a is thermally decomposed in the molecular beam generator 3 as shown in the following formula (2). Therefore, in the growth of GaN _0.02 As _0.98 , that is, the growth in which the composition ratio is Ga: N: As = 50: 1: 49, the ratio of the supply amount by the molecular beam 6 and the molecular beam 8 is GaN powder: Ga = 4. : 46. This means that the shortage of Ga supplied by the molecular beam 6 based on the GaN powder may be supplied by the molecular beam 8 at this ratio.
4GaN powder → (heated at 450 ° C.) → GaN + 3Ga + 3 / 2N ₂ (2)

  Here, in MBE concerning this Embodiment, it is not limited to GNAs, The semiconductor to grow can be variously selected by the change or addition of a raw material. Specifically, the element supplied by the non-nitride gas is not limited to As, and may be a group V element such as P or Sb, or a group III element such as In or Al. Thereby, in the MBE according to the present embodiment, various semiconductors such as GaInNAs, GaInNAsSb, GaInNP, GANASP, AlGaInNP, and AlGaNAs can be grown in addition to GaNAs. In this case, the MBE apparatus 100 includes a plurality of molecular beam generation units 4 according to the supplied elements.

Next, a specific example of the supply amount of each element when a semiconductor other than GaNAs is grown in this way will be described. First, consider the growth of Ga _0.7 In _0.3 N _0.01 As _0.99 as GaInNAs. This growth is a growth in which the composition ratio is Ga: In: N: As = 70: 30: 1: 99. Under the conditions shown in the formula (2), the ratio of supply amount is GaN powder: Ga: It is sufficient to set In = 4: 66: 30. The growth of Ga _0.7 In _0.3 N _0.01 As _0.97 Sb _0.02 as GaInNAsSb is a growth with a composition ratio of Ga: In: N: As: Sb = 70: 30: 1: 97: 2, Under the conditions shown in 2), the ratio of the supply amount may be GaN powder: Ga: In: Sb = 4: 66: 30: 2. Here, the incorporation efficiency of Sb into the crystal is almost 1, and the same handling as that of the group III element is possible (for example, see Non-Patent Document 4).

  As described above, the MBE as the semiconductor manufacturing method according to the present embodiment grows GaNAs2 as a semiconductor on the substrate 1, and therefore, based on the GaN powder 3a as a nitride material containing nitrogen. A nitride gas generating step for generating a molecular beam 6 which is a nitride molecular beam as a nitride gas, and a non-nitride material 4a having As which is an element not included in the GaN powder 3a among the constituent elements of GANAS2 are also included. A non-nitride gas generating step for generating a molecular beam 7 as a non-nitride gas, and a semiconductor growth step for introducing and combining the molecular beams 6 and 7 on the substrate 1 to grow GaNAs 2. . For this reason, it is possible to grow GaNAs 2 having high crystal quality on the substrate 1 without using reactive nitrogen gas activated by high-frequency plasma.

  In addition, MBE as a semiconductor manufacturing method according to the present embodiment is a molecular beam as an auxiliary source gas based on an auxiliary source 5a containing Ga which is an element other than nitrogen among elements contained in GaN powder 3a. 8 includes an auxiliary gas generation step for generating 8 and molecular beams 6 to 8 are introduced and combined on the substrate 1 by the semiconductor growth step to grow GaNAs 2. Therefore, the amount of Ga supplied by the molecular beam 8 is increased. By controlling, GaNAs2 having a desired nitrogen composition ratio even at a high growth temperature state, in particular, GaNAs2 as a dilute nitrogen semiconductor having a nitrogen composition ratio of less than 10% can be grown with high quality and excellent optical characteristics. GaNAs2 can be obtained.

  So far, the best mode for carrying out the present invention has been described as an embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. Is possible.

  For example, in the above-described embodiment, the GaN powder 3a is used as the nitride raw material. However, GaN is not necessarily in the form of powder, and a compound in an arbitrary state such as crystal or amorphous can be used. It is also possible to use a nitride material other than GaN as the nitride material according to the constituent elements of the semiconductor grown on the substrate 1. For example, when the semiconductor to be grown contains In, InN is used. it can.

Further, in the above-described embodiment, it has been described that each constituent element of GaNAs2 is introduced onto the substrate 1 by molecular beams 6 to 8, that is, the GaNAs2 is grown by MBE. Alternatively, it can be grown by other vapor deposition methods such as MOCVD. The mechanism of the molecular beam generator 4 that generates the molecular beam 7 as the non-nitride gas having As described above is not limited to the mechanism using the K cell, but a valve cracker cell (valve cracker). ) Etc. may be used. As the non-nitride material 4a having As, an AsH ₃ gas (arsine gas) material, a GaAs solid material, or the like can be used.

  In the above-described embodiment, the Ga deficiency supplied by the molecular beam 6 based on the GaN powder 3a is supplementarily supplied by the molecular beam 8 based on the auxiliary material 5a. Similarly, when a shortage occurs in N supplied by the molecular beam 6, reactive nitrogen gas obtained by activating nitrogen gas with plasma can be separately supplied. In this case, the MBE apparatus 100 further includes, for example, a nitrogen gas auxiliary supply mechanism having a high-frequency plasma generator, and the MBE as a semiconductor manufacturing method generates reactive nitrogen gas by activating the nitrogen gas with plasma. The reactive nitrogen gas generation step is further included, and in the semiconductor growth step, the reactive nitrogen gas and the molecular beams 6 and 7 are introduced and combined on the substrate 1 to grow the semiconductor. Even when the reactive nitrogen gas activated by the plasma is used as described above, in the semiconductor manufacturing method according to the present invention, the amount of the reactive nitrogen gas applied is smaller than the amount used in the prior art. Therefore, the crystal quality of the semiconductor to be grown can be improved as compared with the prior art.

  Further, in the above-described embodiment, it has been described that the desired Ga / N ratio or the like is obtained in the semiconductor to be grown by supplementarily supplying Ga or N as described above. For example, the N / Ga ratio in the semiconductor may be controlled by changing or changing the temperature of the substrate 1 based on the result shown in FIG.

It is a figure explaining the manufacturing method of the semiconductor concerning an embodiment of the invention. It is a graph which shows the substrate temperature dependence of N / Ga ratio in the GaN film grown on the substrate.

Explanation of symbols

1 Substrate 2 GaNAs
3-5 Molecular beam generator 3a GaN powder 4a Non-nitride material 5a Auxiliary material 6-8 Molecular beam 100 MBE apparatus

Claims (10)

In a method for manufacturing a semiconductor, a semiconductor comprising three or more constituent elements including nitrogen is grown on a substrate by vapor phase growth.
A nitride gas generating step for generating a nitride gas based on a nitride material containing nitrogen; and
A non-nitride gas generation step of generating a non-nitride gas based on a non-nitride material having an element not included in the nitride material among the constituent elements of the semiconductor;
An auxiliary gas generating step for generating an auxiliary raw material gas based on an auxiliary raw material containing an element other than nitrogen among the elements contained in the nitride raw material;
A semiconductor growth step of growing the semiconductor by introducing and combining the nitride gas , the non-nitride gas, and the auxiliary source gas onto the substrate;
Only including, the supply amount of auxiliary raw materials used in the auxiliary gas generation step semiconductor manufacturing method which is characterized in that is controlled according to the temperature of the substrate. In a method for manufacturing a semiconductor, a semiconductor comprising three or more constituent elements including nitrogen is grown on a substrate by vapor phase growth.
A nitride gas generating step for generating a nitride gas based on a nitride material containing nitrogen; and
A non-nitride gas generation step of generating a non-nitride gas based on a non-nitride material having an element not included in the nitride material among the constituent elements of the semiconductor;
A semiconductor growth step of growing the semiconductor by introducing and combining the nitride gas and the non-nitride gas on the substrate;
Only containing an element other than nitrogen contained in the nitride material is a III group element, an element that is not contained in the nitride raw material of the constituent elements of the semiconductor, the group V element and group III element A method for producing a semiconductor, comprising at least one of the methods. In a method for manufacturing a semiconductor, a semiconductor comprising three or more constituent elements including nitrogen is grown on a substrate by vapor phase growth.
A nitride gas generating step for generating a nitride gas based on a nitride material containing nitrogen; and
A non-nitride gas generation step of generating a non-nitride gas based on a non-nitride material having an element not included in the nitride material among the constituent elements of the semiconductor;
A reactive nitrogen gas generation step in which nitrogen gas is activated by plasma to generate reactive nitrogen gas;
A semiconductor growth step of growing the semiconductor by introducing and combining the nitride gas , the non-nitride gas, and the reactive nitrogen gas onto the substrate;
A method for manufacturing a semiconductor, comprising: The nitride gas generating step, the non-nitride gas generation step, and a semiconductor growth step, MBE, MOCVD or a semiconductor process for manufacturing according to claim 1 or 2, characterized in that is carried out by vapor deposition. The said nitride gas production | generation process produces | generates the said nitride gas and non-nitride gas based on the said nitride raw material by heating, The any one of Claims 1-4 characterized by the above-mentioned. Semiconductor manufacturing method. The semiconductor manufacturing method according to claim 2 , wherein the semiconductor including three or more constituent elements including nitrogen is any one of GaNAs, GaInNAs, GaInNAsSb, GaInNP, GANASP, AlGaInNP, and AlGaNAs. The semiconductor manufacturing method according to claim 2 , wherein the nitride material is GaN or InN. The method of manufacturing a semiconductor according to claim 2 , wherein the non-nitride material includes at least one of As, P, Sb, In, or Al. The semiconductor is a semiconductor manufacturing method according to any one of claims 1-8, characterized in that the nitrogen composition ratio is less than 10%. The nitride gas, semiconductor manufacturing method according to any one of claims 1-9, characterized in that the nitride material is a nitride molecular beam that is generated based on.

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