JPS60204694A - Crystal growth device by molecular ray - Google Patents

Abstract

PURPOSE:To control angle-dependent properties of intensity of atomic, molecular, or ionic rays released from a crucible, by attaching collimeters having through holes to the crucible having the interior packed with a raw material for atomic or molecular rays and the outer periphery on which a heater is wound. CONSTITUTION:The Langmuir's crucible 7 consisting of a high-purity material having reaction resistance is packed with the raw material 10 for atomic or molecular rays. The heater 6 is wound on the outer periphery of the crucible. The heater 6 heats the raw material 10 for atomic or molecular rays, evaporates or sublimates it, heats the crucible 7 mainly by heat radiation, and is held by the heater supporting member 13. The first, the second, and the third collimeters 20, 21, and 22 are set in the crucible 7. The collimeters 22 is provided with the plural disklike through-holes 23, and the through-hole 24 at the center, and the first collimeter 20 and the second collimeter 21 are concentrically provided with the plural through-holes 25 and 26, respectively.

Description

[Detailed Description of the Invention] [Technical Portion of the Invention ψt] This invention enables crystal growth by irradiating atoms, molecules, and ion beams onto a substrate in a clean ultra-high vacuum atmosphere.
We will introduce a molecular beam crystal growth device that performs this process.

[Technical background of the invention]

7' By generating an atom/ion beam in a clean ultra-high vacuum atmosphere and irradiating the generated beam onto a cleaned substrate, high quality soybean crystals can be grown. This method is generally called "Molecular Iv crystal growth method" and the equipment used for this is "Molecular A crystal growth apparatus".
It is called.

The feature of such a molecular beam crystal growth method is that the growth rate, growth, thickness, composition, and impurity distribution of the crystal to be grown can be controlled with high precision and reproducibility from the start. Therefore, the molecular beam crystal growth method is used for fabricating high-performance semiconductor devices such as semiconductor lasers and Luminescence high-frequency transistors.

By the way, a typical example of a conventional molecular beam crystal growth apparatus Q is shown in FIG. 1, 7 molecular beam generation sources (also referred to as molecule 1 missing generation cells) 1 corresponding to the types of molecular beam generation 7% i
, 3 is the main structural part. Similarly, in order to create a clean atmosphere, a cooling shroud 2 having a gas adsorption function may be placed around the molecular beam generation source and the virtual part 1 of the substrate holder 4.

When the above-mentioned molecular beam source 1 is enlarged, as shown in Fig. 2, ζ
This is made up of 14, and 7 is a crucible. The crucible 7 generally has a cylindrical shape with a bottom and is called a "Langmuir type." In order to prevent the release of excess impurity gas, the crucible 7 is made of a highly reactive material '15, which is generally Pyrolitech boron nitride (P-BN). Since this P-BN is grown by the vapor phase growth method, the Langmuir shape is most easily obtained as the shape of the '14 pot. Inside such a crucible 7,
Filled with atomic and molecular scarlet raw material IO. A power-rotating heater 6 for heating the raw material IO and allowing it to cool down or cool down is placed around the outer periphery of the crucible 7, and heats the crucible 7 by continuous heat radiation. In order to increase the thermal efficiency, a heat-reflecting reflector 5 is provided on the outside of the heater 6, which is made of several layers of 1>11 tantalum foil or the like, which is a high-purity 7-crystalline heat-resistant metal. . Further, a thermal face protector 9 is provided on the outside of the bottom of the crucible 7, and a heat face protector 9 provided at the tip of the heat protector 9 is in contact with the bottom surface of the crucible 7. .

Similarly, the composition ratio of atoms, molecules, and ions in the beam emitted from the molecular beam source 1 can be changed by making appropriate modifications to the inside and outside of the molecular beam source 1. Generally, one molecule υC is generated by heating the bottomed cylindrical pot 7 with the heater 6, unless it is. is used.

In this case, the ・x11 for atoms, molecules, and ions is the raw material I.
Since O and the heating temperature e+, T is almost constant.

During operation, the beam emitted from the molecular beam source 1 is opened and closed by the shutter 4, and enters the No. 4 plate time keeping mechanism section 1 that holds and heats the base for growing the crystal. Of the emitted beams, the portions that are reflected by the substrate holding mechanism 1 or the 5th beam or that do not enter the substrate holding mechanism section J are captured by the shroud 2 that is cooled with nitrogen sparge. When the raw material 10 is a high vapor pressure material such as 94 or 100%, the cooling shroud 2 plays an important role in keeping the atmosphere in the system constant.

[1t 7] The above conventional Lanckmuir crucible 7 has 1. 'The degree of crystal sheath -
For the intermolecular crystal growth method that aims at II4 thickness control, the following entry points are considered.

(1) Steam the raw material 1° filled in the Lancmuir type crucible 7 to create an atomic/molecular beam in the first crucible 7 [;14
When emitted from 0fil
There is. This dependence of the beam intensity on rounded corners is due to the fact that the evaporated atomic/molecular beam collides with the inner wall 7b of the Langmuir crucible 7 and regenerates into radiation powder. I have been working for three years from my current home where I live. Rankmuir type”! Atoms emitted from 4-hole 7.
The molecular beam intensity) becomes non-uniform on the plate, and becomes uniform 1
It is difficult to subtract 1α thickness by 1! It is ili.

■ The reason why the atom-molecule beam from the Rankmuir crucible 7 has peak-degree dependence is because the atom-molecule beam interacts with the inner wall 7b of the crucible 7. Distance between surface and opening 137a e%'#j
Depending on the inner diameter 2r of the basin 7, there is a change in dependence on the angle as shown in FIG. Therefore, as the Kagi 110 is depleted, the intensity of the atomic/molecular beam changes (a), which poses a serious problem in molecular beam crystal growth.

[Purpose of the invention]

The purpose of this invention is to develop a molecular crystallization system that can control the angle of the strong I(angle) of atoms, molecules, and ion beams emitted from a crucible to meet a desired purpose. It is a place that provides c.

[Summary of the invention, polishing] The present invention is a crystallization device including one or more collimators having only one or more holes in the crucible.

[Embodiments of the invention]

The molecular powder crystallization apparatus of the present invention also has a plurality of molecular beam generation source power shafts installed in the end-holding mechanism section, as in the prior art, and it is necessary to keep the vessel as clean as possible. In order to create an atmosphere, gas absorbers are installed around the substrate holding mechanism and the molecular beam generation source.
An effective cooling shroud is provided.

In the present invention, the above-mentioned molecular beam generation source is constructed as shown in Fig. 4, and the same parts as in the conventional example (Fig. 2) are given the same reference numerals. That is, a Langmuir type crucible 7 made of a reaction-resistant, high-purity material such as pyrolyzol boron nitride (P-BN) is filled with atomic/molecular beam raw material IO. A heater 6 is wound around the outer periphery of the crucible 7. This heater 6 has the above-mentioned atoms and
It is for heating the molecular beam raw material 10 to evaporate or sublimate it, and the crucible 7 is mainly heated by thermal radiation, but in this invention it is held by a heater holder 13 as shown in (2). The heater holder 13 is made of pyroresin boron nitride (P-BN) and has a spiral groove on its inner surface, and the heater 6 is fixed within the heater holder 13. A heat reflective reflector 12 is disposed outside the heater 6, that is, the heater holder 13. This heat reflection reflector 12 has a double structure and has a cylindrical shape with a bottom.
．． A cooling medium supplying vibrator 18 and a cooling medium discharging vibrator 19 are arranged at both ends of the 2aj, and the cooling medium 16 is filled inside through the supplying vibrator 18. A rod-shaped thermocouple protector 9 is inserted, and the thermocouple 8 provided at the tip of the thermocouple protector 9 is in contact with the bottom surface of the crucible 7. Further, one end of the heater 6 is inserted through the bottom portion 12a, and this one end is further connected to the heater phase current supply member 4.
It is connected to.

The reflector support 15 has been inserted after repairing the upper discharge part 12a. 11 is a heat conduction shielding ring.

Historically, in this invention, a disk-shaped first holder is provided in the first chamber 7. Second. A third collimator 20, 21, 22 is arranged. The valley collimators 20, 21 and 22 are made of pyrolithic boron nitride (P-BN) like the crucible 7, and are each constructed as shown in FIG.

That is, the collimator 22 of the conduit 3 has a disk shape and has a plurality of circular through holes 23 so as to suppress the release of particulate matter due to bumping of the raw material 10 and to smooth the evaporation beam intensity distribution. are arranged concentrically. Through hole 23
is 8, but the number of through holes 23 is equal to the diameter 2 of the through holes 23.
r.

can be increased or decreased depending on the desired beam intensity distribution. A through hole 24 having a diameter of 2r3' is provided at the center of ψ, and the size relationship between r3 and r3' is determined by the number and arrangement radius of the through holes 23 having an inner diameter of 2r3.

The first collimator 20 and the second collimator 21ζ are provided with four concentric holes 25 and 26 having diameters of 2rH and 2r2, respectively.

In this implementation example 11, rl>r2, but the through hole 25°2
Number of 6, arrangement radius, e, 12. Depending on the relationship between g and
e3 is the distance between the second collimator 21 and the third collimator 22, and the distance relationship between g, , g, , and e is determined by controlling the emitted beam intensity distribution, etc. There is a strong correlation with optical parameters such as the number of through holes, arrangement radius, and hole diameter of each collimator 20, 21, and 22.

'1 + h + 'sO position ic each column' J l 920
, 21°22, the following relational expression may be used. That is, ・Jf of crucible 7: portion diameter 2RN% opening diameter 2
RO% crucible length e. and the position of the collimator (diameter 2R61,)
+'(lx relationship is determined by
>Since it supports the tapered shape of RN, lx can be easily set.

In the example shown in Figures 4 and 5, the hole diameter of the third collimator 22 is designed to be small so that the evaporation vapor pressure of the raw material 10 is close to the equilibrium state, so that the raw material 1θ
The evaporation vapor pressure can be controlled only by the heating temperature, regardless of the depletion state ζ. Hole 4i 2 r + of each through hole 25.26 of first collimator 26 and second collimator 21
, 2 r2 and d number of hole sides, arrangement half-tone, collimator interval e
2 is determined so that the intensity distribution of the evaporation beam becomes more or less uniform on the cutting board.

Next, FIGS. 6(a) to (fl) show other embodiments of the collimator. That is, FIGS. 6(a) and 6(b) show circular through holes 27 and 2B of the same diameter, respectively, axially symmetrically. The collimators 29 and 30 are arranged.(c) shows the circular through holes 3 with different diameters.
This is a collimator 33 in which 1.32 is arranged axially symmetrically.

(d) is a collimator 36 in which a regular hexagonal through-hole 34 is arranged at the center, and circular through-holes 35 are arranged concentrically and axially symmetrically around the hexagonal through-hole 34 . (e) shows circular through holes 37, 3 with different diameters.
8.39 is a collimator 40 with non-uniform distribution.

In (f), a regular square through hole 41 is arranged in the center, and the surrounding area ζ
This is a collimator 43 in which regular triangular through holes 42 are arranged concentrically and symmetrically about this axis. As described above, the collimator has a wide variety of hole shapes, arrangement patterns, and number of holes, and the degree of freedom in controlling the beam intensity distribution can be extremely increased. Therefore, the number of through holes is not limited to a plurality, and may be one.

In addition, the collimator does not necessarily have to be a disc, and the collimator is not necessarily a disc.
A similar effect can be expected with a collimator 45 that is a cylinder with a bottom and covers a plurality of circular through holes 44 as shown in the figure.

The number of collimators provided in the crucible 7 is not limited to a plurality of collimators, but may be one.

Similarly, the molecular beam crystal growth apparatus of the present invention has the same structure as the conventional example (FIG. 1) except for the above molecular beam generation source, so detailed explanation will be omitted.

Generally speaking, molecular beam crystal growth is not good at handling high vapor pressure substances such as phosphorus and sulfur.

That is, in the case of phosphorus, since the adhesion coefficient is small, it is scattered within the molecular beam crystal growth apparatus or remains within the system. However, by controlling the molecular beam intensity according to the present invention, it is possible to almost eliminate the proportion of the molecular beam emitted to areas other than the substrate, and the above problem has been significantly improved. Father, sulfur is preheated to the system at a temperature of f (200-250 °C) TeI O-3 to 10-2f.
i pressure is reached, and beam intensity l used for crystal growth is reached. However, in this invention, the collimator is 20°21.2
Since the beam intensity can be suppressed by providing ζ, the above problem can be overcome. In the above embodiment, the temperature of the crucible for sulfur during growth had to be raised to 500 to 600°C, but it became possible to purify the raw material 10 by heating and degassing it, and the quality of the produced crystals was improved.

In addition, by using the collimators 20, 21, and 22, it becomes easier to grow mixed crystals such as GaIn, -xAsPx, and ZnS, which was previously difficult, and application of the molecular beam crystal growth method 1.
We were able to dramatically expand our daughter area.

〔Effect of the invention〕

According to this invention, there are one or more through holes 23 in the crucible 2.
, '24, 25, 26, the provision of one or more collimators 20, 21, 22 has the following excellent effects.

■ The intensity distribution of atoms, molecules, and ion beams emitted from a molecular beam source can be controlled to meet the desired purpose.

■ Thermal equilibrium vapor pressure, which cannot be obtained with a Langmuir crucible, can be controlled within the crucible z.

■ Since the beam intensity of high vapor pressure substances such as phosphorus and sulfur can be controlled by inserting collimators 20, 21, and 22, it has become easier to handle phosphorus and sulfur raw materials in molecular beam crystal growth.

- Since the structure of the collimators 20, 21, and 22 is simple and simple, they can be easily obtained and assembled at low cost.

■ Through holes 23 for the collimators 20, 21, 22ζ.
24, 25, 26 shape, number, arrangement and collimator 20
, 21, 22, the degree of freedom in combination of numbers is almost infinite, and therefore the beam intensity distribution can also be freely set.

(2) Crystal growth of GaIn, xAsPx, InP%ZnS, etc. has become easier.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional molecular beam crystal growth apparatus and a molecular beam crystal growth apparatus used to explain the present invention, FIG. 2 is a sectional view showing a molecular beam generation source used in a conventional molecular beam crystal growth apparatus, and FIG. Figure 3 is a characteristic curve diagram showing the intensity distribution of the beam emitted from a conventional molecular beam generation source, and Figure 4 shows the main parts (molecular beam generation source) of a molecular beam crystal growth apparatus according to an embodiment of the present invention. 5 is a perspective view showing a collimator used in the molecular beam generation source in this invention, and FIGS. 6(a) to (f)
1 is a plan view showing another embodiment of the collimator, and FIG. 7 is a perspective view showing another embodiment of the collimator. 1... Board holding mechanism section, 2... Cooling shroud,!
... Molecular beam source, 4... Shutter, 6... Heater, 7... Crucible, 8... Thermocouple, 9... Thermocouple hoki body, 10... Electron. Molecular beam raw material, 12...
Heat reflective reflector, 20, 21.22... collimator, 23.24, 25.26... through hole. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure M 5

Claims (1)

[Claims] (1) At least the substrate holding mechanism and the atoms and
A molecular beam system in which a heater is wound around the outer periphery of a crucible filled with a molecular beam raw material, and a molecular beam generation source is arranged facing each other, which is a cylindrical heat-reflecting reflector provided on the outside of the heater. A molecular beam crystal growth apparatus, characterized in that the crucible is provided with one or more collimators for forming one or more through holes.