JPH0383326A - Vapor growth process for organic metal - Google Patents

Abstract

PURPOSE:To enable the group V composition of InGaAsP four element mixed crystal to be controlled with high precision even at low temperature by a method wherein organic group V element is used as group V material in order to grow InGaAsP by applying the vapor growth process of organic metal (MOVPE). CONSTITUTION:InGaAsP four element mixed crystal lattice matching with InP is grown using organic group V element as a group V material. As for the organic group V metallic material, TBP(CH3)3CPH2) and TBA(CH3)3CAsH2) are used. The dissolving efficiency of group V organic material starts to change notably at the temperature not exceeding 400 deg.C while the dissolving efficiency of AsH3 equals to that of PH3 at the temperature exceeding 400 deg.C. The controllability of solid composition of As and P at low temperature is equally excellent to that of group III element so that As and P may be effectively applied to the manufacture of high performance photosemiconductor device requiring of the low temperature growth of crystal.

Description

[Detailed Description of the Invention] [Summary] Metal-organic vapor phase growth method suitable for obtaining IncaAsP quaternary mixed crystal that is lattice-matched to InP, which is important as a constituent material of optical communication devices used in the 1 [μm] band. With regard to InP, the purpose of this study is to precisely control the I-group composition of the IncaAs P quaternary mixed crystal even at low temperatures.
It is configured to grow an nGaAsP quaternary mixed crystal.

[Industrial application field]

The present invention utilizes InGaA, which is lattice-matched to InP, which is important as a constituent material of optical communication devices used in the 1 [μm] band.
The present invention relates to an organometallic vapor phase growth method suitable for obtaining sP quaternary mixed crystals.

Currently, as optical communication systems increase in speed and capacity, there is a demand for higher performance of optical semiconductor devices. In order to meet this demand, we have developed techniques for growing crystals, which are the structural materials for optical semiconductor devices, such as metalorganic vapor phase epitaxy (metallo), which has excellent controllability in terms of thickness, composition, carrier concentration, etc.
rganic vapor phase eptta
Research and development of xy:MOVPE) method is active.

In principle, the MOVPE method can exhibit the above-mentioned characteristics because raw materials are supplied in the gas phase, but depending on the growth temperature, composition range, etc., the controllability becomes poor. I end up.

For example, distributed feedback (distributed feedback), which aims to improve performance by stacking an active layer on a diffraction grating,
eedback: DFB) type laser, or an MQW (multi quantum well) type laser with an active layer having a multiple quantum well structure.
In order to manufacture tum we I) type lasers, etc., it is necessary to grow the crystals that make up the laser at low temperatures. Controllability worsens in the vicinity of the precepts.

Therefore, a MOVPE method with good controllability even at low temperatures must be developed.

[Prior art] Conventionally, when growing InGaAs P by applying the MOVPE method, organic metals containing group III elements, such as In, are used as a raw material for the growth of InGaAs P. ) s I n),
Or triethylindium (TEIn: (Ct Hs )z In), Ga
For example, trimethyl gallium (TMGa: (CH3) 3 Ga) or triethyl gallium (TEGa: (Cz Hs) 2 Ga) is used;
For As, arsine (ASH3) is used, and for P, phosphine (PH,) is used.

When using the raw materials as described above, in the MOVPE method,
The relationship between gas phase composition and solid phase Hl is expressed as follows.

Here, X and y are solid phase compositions, and InGaAs
These are X and y when P is expressed as I J-, Ga, AS+-y Py. Also, (Ga).

(In), (P), and (As) are the gas phase compositions near the InP substrate, and the respective introduced raw material gas concentrations are (TEGa)
.

(TMIn).

(PH,].

When (A s Hl), (Ga) x77,, (TEGa)
...(3)(I n) x77.11(TM I n
) ... (4) [P] = ηP (PHs)
・ ・ ・ ・(5)(As)=
77,, (AsHx) ・ ・ ・
・It is expressed as in (6). Of course, in this case, it is assumed that TEGa and TMIn are used as the raw materials for Ga and In. Here, η indicates the decomposition efficiency of each source gas. When implementing the MOVPE method, the quantities to be practically controlled are (TEGa), (TM I n), (
Since PHs ) and (As Hx ),
The relational expressions obtained by substituting the above equations (3) to (6) into the above equations (1) and (2) give realistic relationships between the gas phase and the solid phase. That is, (0≦X≦0゜47) (8) Fig. 2 actually shows TEGa, TMIn, Ash, and so on.

In the growth of InGaAsP using PHs, X and (
TMIn)/(TEGa), y and (Ashs)/(PH1). The vertical axis is X or y, and the horizontal axis is (TMIn)/(TEGa). )
Alternatively, (AsHs)/(PHs) are respectively taken. Note that the growth temperature is 620 ('C).

In the figure, for the ■ group, if ηl++/ηG is the fitting parameter, then η17/ηG! =i1
A quantitative explanation is possible if This shows that the organometallic compound that is the raw material for group II has approximately the same decomposition efficiency as 620 (''C).On the other hand, for group II, the experimental results show that ηAs/η and ξlO are not used. cannot be explained, indicating that the decomposition efficiency of PHs is about 1/10 compared to ASH3.

Therefore, composition control on the V-line side is particularly poor in the region of y>0.5 even at a temperature of 620 ('C). That is, the variation in y is large with respect to the change in (As H2)/[PH3], and a small change in the supply amount causes a large change in the solid phase composition.

[Problem to be solved by the invention]

As mentioned above, η□/η2, that is, A s Hs and P
The difference in thermal decomposition efficiency with H, is 10 at a temperature of 620 ('C), and becomes even larger when the temperature is lower than that, Ea: activation energy: Boltzmann's constant T: temperature (K) It changes according to the relationship expressed by the formula. Therefore, as the temperature becomes lower, it becomes more difficult to control the solid phase composition of group V as long as ASH3 and PH are used as raw materials.

The present invention shows that even at low temperatures, the V of InGaAsP quaternary mixed crystal
Suppose that it would be possible to precisely control the tribal precepts.

[Means to solve the problem]

To solve the problems mentioned above, AsHl and PHI
In a low temperature region where the difference in decomposition efficiency with I is large, it is preferable to use an organic group V as the raw material.

Therefore, in the MOVPE method according to the present invention, InGaAsP, which is lattice-matched to InP, uses organic group III as the raw material.
Either growing a quaternary mixed crystal or using an organic group III as a raw material, and ηAs/ 77F = a-e x
p (Ea/kTe )η□/ηPξ10 η□: Decomposition efficiency of ASH3 ηP: Decomposition efficiency of PHZ Ea: Activation energy = 1.0 (eV) k: Boltzmann constant a: Proportional coefficient = 6.9XIO' InGaAsP quaternary mixed crystal, which is lattice-matched to InP, is grown at a temperature below the temperature Tc.

[Effect]

By adopting the above method, there is no difference in the decomposition efficiency of the V-mixed raw material even at low temperatures, and η□/η, ξ1 can be achieved. The controllability is as good as that of group Ⅰ, and it is effective when applied to the production of high-performance optical semiconductor devices that require low-temperature growth of crystals.

〔Example〕

An example in which an InGaAsP quaternary mixed crystal is grown will be described.

■ As the raw material, TMIn and TEGa are used as before.
Use.

As an organic kneading raw material, TBP (tertiarybu
tyl-phosphine: (CM.

), CPH, ) and TBA (tertiarybut
yl-arsine: (CH3)* CASH3)
Use.

The temperature at which the decomposition efficiency of the organic kneaded raw material begins to vary greatly is 400 ("C) or lower, and at temperatures above that, as far as the amount η□'/η,' is concerned, η□ ′／
η, ′ξ1. direction, η□′ and η,
' represents the decomposition efficiency of TBA and TBP.

Figure 1 uses the above-mentioned raw materials and the temperature is 500 [°C].
This is a diagram showing the relationship between the solid phase set tcy and the raw material vapor phase ratio (TBA)/(TBP) when growing an InGaAsP quaternary mixed crystal, with y on the vertical axis and y on the horizontal axis. (T
BA)/(TBP) respectively.

Here, if η□'/η,' is calculated according to the formula, the experimental results shown in FIG. 1 can be explained by η□'/η,'''=,1.

This means that even at a low temperature of, for example, 500 ("C),
It has been shown that by using organic group V as the raw material for mixing (1), it is possible to grow a group V solid phase with the same controllability as the group (2) composition.

〔Effect of the invention〕

In the organometallic vapor phase growth method according to the present invention,
AAs P quaternary mixed crystal is grown.

By adopting the above structure, there is no difference in decomposition efficiency of the V-mixed raw material even at low temperatures, and η□/η,! = il, the controllability of the solid phase composition of As and P at low temperatures is as good as that of group II, and this makes it possible to manufacture high-performance optical semiconductor devices that require low-temperature growth of crystals. It is applicable and effective.

[Brief Description of the Drawings] Figure 1 shows the relationship between the solid phase composition y and the raw material vapor phase ratio [TBA]/[TBP] when InGaAsP quaternary mixed crystal is grown according to an embodiment of the present invention. Figure 2 is a diagram to explain the phase composition X or solid phase composition y and the raw material vapor phase ratio [TMIn]/(TEGa) when InGaAsP quaternary mixed crystal is grown using the conventional technique. Alternatively, it is a diagram for explaining the relationship between raw material gas phase ratio (AsH2)/(PH3).

Claims (2)

[Claims] (1) An organometallic vapor phase growth method in which an organic group V material is used as a group V source material to grow an InGaAsP quaternary mixed crystal that is lattice-matched to InP. (2) Using organic group V as the group V raw material, and η_A_
s/η_P=a・exp(-Ea/kTc)η_A_s
/η_P≒10 η_A_s: Decomposition efficiency of A_SH_3 η_P: Decomposition efficiency of PH_3 Ea: Activation energy = 1.0 [eV] k: Boltzmann constant a: Proportionality coefficient = 6.9 x 10^4 Below the temperature T_C A metal organic vapor phase growth method for growing an InGaAsP quaternary mixed crystal lattice-matched to InP at a temperature of .