JPH04247403A - Formation of semiconductor distributed reflection mirror and device used therein - Google Patents

Abstract

PURPOSE:To provide the semiconductor distributed reflection mirror having a high- accuracy central wavelength by obtaining the detection output of the IR intensity expressing the optical thicknesses of semiconductor layers with desired high accuracy and controlling the supply of molecules and atoms by the detection output, thereby forming the semiconductor layers to the optical thicknesses of high accuracy in the case of formation of the semiconductor distributed reflection mirror 21 laminated and formed successively alternately with the semiconductor layers 22H having a high refractive index and the semiconductor layers 22L having a low refractive index on a semiconductor substrate by an epitaxial growth method. CONSTITUTION:The detection output of the optical thicknesses of the semiconductor layers which are being formed on the semiconductor substrate 20 to be used for controlling the supply of the molecules and atoms constituting the semiconductors forming the semiconductor layers is obtd. from the intensity of the IR rays obtd. by passing the IR rays radiated through the semiconductor substrate 20 and the semiconductor layers which are being formed thereon from a substrate heating means 40 through a band-pass filter having the central wavelength equal to the central wavelength of the semiconductor distributed reflection mirror 21.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention forms a semiconductor distributed reflector having a structure in which semiconductor layers having a high refractive index and semiconductor layers having a low refractive index are sequentially and alternately laminated on a semiconductor substrate. The present invention relates to a method and an apparatus used therefor.

0002

2. Description of the Related Art Conventionally, the following method for forming a semiconductor distributed reflector using an apparatus for forming a semiconductor distributed reflector, which will be described below with reference to FIG. 4, has been proposed.

First, a conventional semiconductor distributed reflector forming apparatus will be described. That is, it has a vacuum vessel 10 connected to an evacuation means (not shown) and the like.

[0004] The device also includes a substrate mounting means 30 which is disposed within the vacuum container 10 and on which the semiconductor substrate 20 is placed.

The substrate mounting means 30 is supported by support means (not shown) provided in the vacuum container 10, has a substrate mounting surface 32, and is constructed using a substrate mounting table 31 made of, for example, molybdenum. has been done. The semiconductor substrate 20 is fixed onto the substrate mounting surface 32 of the substrate mounting table 31 using, for example, a solder layer 33.
It will be placed.

Furthermore, a substrate heating means 40 is provided for heating the semiconductor substrate 20 placed on the substrate mounting table 31 constituting the substrate mounting means 30 as described above.

This substrate heating means 40 is connected to the substrate mounting table 31.
It is constructed using a heater 41 that is housed inside and generates heat when energized.

[0008] Furthermore, molecules or atoms constituting the semiconductor forming the semiconductor layer 22H having a high refractive index are placed on the semiconductor substrate 20 placed on the substrate mounting table 31 constituting the substrate mounting means 30. , molecules or atoms constituting the semiconductor forming the semiconductor layer 22L having a low refractive index, the semiconductor layer 22H having a high refractive index and the semiconductor layer 2 having a low refractive index.
2L are sequentially and alternately laminated by an epitaxial growth method, whereby semiconductor layers 22H having a high refractive index and semiconductor layers 22L having a low refractive index are sequentially and alternately laminated. It has a means 50 for supplying semiconductor constituent molecules or atoms sequentially and alternately so that atoms 21 are formed.

This semiconductor constituent molecule or atom supply means 50
is a molecular beam (generally referred to as BH) due to molecules constituting the semiconductor forming the semiconductor layer 22H having a high refractive index, and a molecular beam (generally referred to as BH) due to molecules constituting the semiconductor forming the semiconductor layer 22L having a low refractive index. For example, a Knudsen cell is installed in the vacuum chamber 10 so that both the molecular beams BH and BL irradiate onto the semiconductor substrate 20 placed on the substrate mounting table 31. a shutter 52H that opens and closes the path of the molecular beam between the molecular beam sources 51H and 51L and the semiconductor substrate 20, respectively.
and 52L.

Furthermore, the molecular beam B from the molecular beam generation source 51H constituting the semiconductor component molecule or atom supply means 50
A semiconductor layer 22H having a high refractive index is formed on the semiconductor substrate 20 by irradiating the semiconductor substrate 20 placed on the substrate mounting table 31 constituting the substrate mounting means 30 with H. supplies the molecules that make up the
As a result, when the semiconductor layer 22H having a high refractive index is being formed on the semiconductor substrate 20, the optical thickness of the semiconductor layer 22H having a high refractive index being formed on the semiconductor substrate 20 is detected, and the molecular - Irradiating the semiconductor substrate 20 placed on the substrate mounting table 31 forming the substrate mounting means 30 with the molecular beam BL from the molecular beam generation source 51L forming the atom supply means 50; Accordingly, a semiconductor layer 2 having a low refractive index is formed on a semiconductor substrate 20.
While supplying the molecules constituting the semiconductor forming 2L,
When the semiconductor layer 22L having a low refractive index is thereby formed on the semiconductor substrate 20, the optical thickness is used to detect the optical thickness of the semiconductor layer 22L having a low refractive index that is being formed on the semiconductor substrate 20. It has a detection means 60.

This optical thickness detection means 60 includes (i)
A monochromatic light source 61 arranged outside the vacuum vessel 10 , a monochromatic light introducing window 62 provided in the vacuum vessel 10 , and a monochromatic light source 61 between the monochromatic light source 61 and the monochromatic light introducing window 62 It has a monochromatic ray optical path 63 for a monochromatic ray (this is referred to as L), and an optical chopper 64 and an optical lens 65 arranged in the monochromatic ray optical path 63,
A monochromatic beam irradiation means 60A in which the optical axis of the monochromatic beam optical path 63 and the monochromatic beam introducing window 62 is set so that the monochromatic beam L from the monochromatic beam 61 irradiates onto the semiconductor substrate 20.
and (ii) a monochromatic light guiding window 66 provided in the vacuum vessel 10, a monochromatic light detector 67 disposed outside the vacuum vessel 10, a monochromatic light guiding window 66, and a monochromatic beam detector 67.
an optical path 68 for monochromatic rays (this is referred to as L') guided out of the vacuum vessel 10 from inside the vacuum vessel 10 through the monochromatic light guiding window 66; When the semiconductor substrate 20 is irradiated with the monochromatic light L, the reflected light obtained by being reflected from the semiconductor substrate 20 side is the monochromatic light L' described above. Monochromatic ray detector 67
A monochromatic beam receiving means 6 in which the optical axes of the monochromatic beam guiding window 66 and the monochromatic beam optical path 68 are set so as to be incident on the monochromatic beam receiving means 6.
0B, and (iii) when forming a semiconductor layer 22H having a high refractive index on the semiconductor substrate 20 from the monochromatic beam detector 67 of the monochromatic beam receiving means 60B,
When a detection output DH representing the optical thickness of the semiconductor layer 22H being formed on the semiconductor substrate 20 is output and a semiconductor layer 22L having a low refractive index is formed on the semiconductor substrate 20, the semiconductor substrate The semiconductor layer 22L is configured to output a detection output DL representing the optical thickness of the semiconductor layer 22L being formed on the semiconductor layer 20.

Note that the detection outputs DH and DL from the monochromatic beam detector 67 represent the optical thicknesses of the semiconductor layers 22H and 22L, respectively, which are being formed on the semiconductor substrate 20. Semiconductor layers 22H and 22
The respective intensities of the monochromatic light rays L' obtained when forming the respective monochromatic rays L take different values depending on the respective thicknesses of the semiconductor layers 22H and 22L. 67
The different detection outputs DH and DL are different values corresponding to the different intensities of the monochromatic light beam L' obtained when the semiconductor layers 22H and 22L are formed on the semiconductor substrate 20, respectively. This is because it takes .

Furthermore, the detection of the semiconductor layer 22H having a high refractive index, which is being formed on the semiconductor substrate 20, is obtained from the monochromatic beam detector 67 of the monochromatic beam receiving means 60B constituting the optical thickness detecting means 60. Based on the detection output DH representing the optical thickness and the detection output DL representing the optical thickness of the semiconductor layer 22L having a low refractive index being formed on the semiconductor substrate 20, the above-mentioned Supply of the molecular beam BH onto the semiconductor substrate 20 from the molecular beam source 51H constituting the molecular or atom supply means 50 and the supply of the molecular beam BL onto the semiconductor substrate 20 from the molecular beam source 51L. Semiconductor constituent molecules that control the supply of molecules constituting the semiconductor forming the semiconductor layer 22H having a high refractive index and molecules constituting the semiconductor forming the semiconductor layer 22L having a low refractive index onto the semiconductor substrate 20. It has an atom supply control means 70.

This semiconductor constituent molecule or atom supply control means 70 is configured such that when a detection output DH representing the thickness of the semiconductor layer 22H is obtained from the monochromatic light detector 67, the detection output DH indicates the thickness of the semiconductor layer 22H. It is detected that the value representing the planned thickness has been reached, and based on the detection output, the shutter 52H constituting the above-mentioned molecule or atom supply means 50 is controlled from the open state to the closed state, and the shutter 5
2L is controlled from the closed state to the open state, and when the detection output DL representing the thickness of the semiconductor layer 22L is obtained from the monochromatic light detector 67, the detection output DL indicates the thickness of the semiconductor layer 22L. It is detected that the value representing the planned thickness has been reached, and based on the detection output, the shutter 52L constituting the above-mentioned molecule or atom supply means 50 is controlled from the open state to the closed state, and the shutter 52H is configured using a control/drive circuit 71 that controls the switch 52H from a closed state to an open state.

The above is the configuration of the conventionally proposed device for forming a semiconductor distributed reflecting mirror.

Next, a conventional method for forming a semiconductor distributed reflector using the above-described conventional semiconductor distributed reflector forming apparatus will be described.

In the conventional semiconductor distributed reflector forming method, the heater 41 constituting the substrate heating means 40 is energized to generate heat, and the semiconductor substrate 20 is heated to a predetermined temperature by the heat. Then, from the molecular beam source 51H constituting the semiconductor constituent molecules or atom supply means 50, a molecular beam BH from molecules constituting the semiconductor forming the semiconductor layer 22H having a high refractive index and a semiconductor layer having a low refractive index are emitted. 2
Molecular beam BL by molecules constituting the semiconductor forming 2L
The molecular beams BH and BL are sequentially and alternately generated on the semiconductor substrate 20 by opening and closing the shutter 52 each time the molecular beams BH and BL are generated alternately. molecules constituting the semiconductor and the semiconductor layer 22 having a low refractive index to form a semiconductor layer 22H having a high refractive index on the semiconductor substrate 20.
The semiconductor layer 22H having a high refractive index is sequentially and alternately supplied with the molecules constituting the semiconductor forming the semiconductor layer 22H.
A semiconductor layer 22H having a high refractive index and a semiconductor layer 22L having a low refractive index are sequentially and alternately stacked by an epitaxial growth method. A semiconductor distributed reflector 21 having a configuration shown in FIG.

In this case, the semiconductor layer 22 having a high refractive index
Even when forming the semiconductor layer 22L having a low refractive index, the monochromatic light beam L is emitted onto the semiconductor substrate by the monochromatic light irradiation means 60A constituting the optical thickness detection means 60. 20 and thereby reflected from the semiconductor substrate 20 side, the monochromatic light receiving means 60B constituting the optical thickness detecting means 60 receives the monochromatic light L', thereby: A semiconductor layer 22H having a high refractive index on the semiconductor substrate 20
, a detection output DH representing the thickness of the semiconductor layer 22H being formed on the semiconductor substrate 20 is obtained from the monochromatic light detector 67 of the monochromatic light receiving means 60B, and When the semiconductor layer 22L having a low refractive index is formed thereon, from the monochromatic light detector 67,
The detection output DL representing the thickness of the semiconductor layer 22L being formed on the semiconductor substrate 20 is obtained, and based on these detection outputs DH and DL, the semiconductor constituent molecules or atoms supply control means 70 is controlled. By the control/drive circuit 71,
The opening and closing of the shutters 52H and 52L are controlled in an inverse relationship to each other, so that the molecular beams BH and BL are sequentially and alternately irradiated, and therefore the molecules constituting the semiconductor forming the semiconductor layer 22H having a high refractive index are , a semiconductor layer 2 having a low refractive index
The sequential and alternating supply of molecules constituting the semiconductor forming 2L is controlled.

As described above, the conventional method for forming a semiconductor distributed reflector and the apparatus for forming a semiconductor distributed reflector used therein have been clarified.

According to the above-described conventional method for forming a semiconductor distributed reflector and the apparatus for forming a semiconductor distributed reflector used therein,
Since it is clear from the above, a detailed explanation will be omitted, but the semiconductor layer 22H having a high refractive index and the semiconductor layer 22L having a low refractive index are sequentially and alternately formed on the semiconductor substrate 20 at a predetermined wavelength (this wavelength). Therefore, the semiconductor layer 22H having a high refractive index and the semiconductor layer 22L having a low refractive index are sequentially and alternately stacked on the semiconductor substrate 20. It is possible to form the semiconductor distributed reflector 21 having the wavelength λ as the center wavelength.

[0021]

[Problems to be Solved by the Invention] In the case of the conventional semiconductor distributed reflector forming method and the semiconductor distributed reflector forming apparatus used therein, in order to constitute the optical thickness detection means 60, (i) vacuum vessel 10; An external monochromatic light source 61, a monochromatic light introduction window 62 provided in the vacuum container 10, and a monochromatic light source 6
(ii) a monochromatic beam emitting window 66 provided in the vacuum vessel 10 and a monochromatic beam detector 82 outside the vacuum vessel 10; and a monochromatic beam receiving means 6 having an optical path 68 between a monochromatic beam guiding window 66 and a monochromatic beam detector 82.
Since it is necessary to provide 0B, the optical thickness detection means 6
0 had the drawbacks of being expensive, large, and complicated.

Furthermore, in the optical thickness detection means 60,
The monochromatic light beam L from the monochromatic light beam irradiation means 60A is irradiated onto the semiconductor substrate 20, and the monochromatic light beam L' that is the reflected light is emitted.
Since the monochromatic light beam is received by the monochromatic light receiving means 60B, the substrate mounting table 31 constituting the substrate mounting means 30
, a monochromatic light irradiation means 60A and a monochromatic light receiving means 60.
Fine adjustments are required to set the direction of B with respect to the optical axis and to place the semiconductor substrate 20 on the substrate mounting table 31.
It had the disadvantage of being difficult.

Furthermore, for this reason, the optical thickness detection means 6
The semiconductor layer 22 having a high refractive index obtained from the monochromatic beam detector 67 of the monochromatic beam receiving means 60B constituting the
The detection outputs DH and DL, which separately represent the optical thicknesses of the semiconductor layer 22H having a high refractive index and the low refractive index, cannot be obtained at the expected values. It is difficult to form the semiconductor layer 22L with the desired highly accurate optical thickness, and therefore it is difficult to form the semiconductor distributed reflector 21 with the desired highly accurate center wavelength λ. It had the disadvantage of being.

Therefore, the present invention aims to propose a novel method for forming a semiconductor distributed reflector and an apparatus for forming a semiconductor distributed reflector using the same, which is free from the above-mentioned drawbacks.

[0025]

[Means for Solving the Problems] The method for forming a semiconductor distributed reflector according to the present invention is similar to the conventional method for forming a semiconductor distributed reflector described above with reference to FIG. Molecules or atoms constituting a semiconductor forming a semiconductor layer having a high refractive index and molecules or atoms constituting a semiconductor forming a semiconductor layer having a low refractive index are sequentially and alternately supplied to the above. The semiconductor layer having the high refractive index and the semiconductor layer having the low refractive index are sequentially and alternately stacked on the semiconductor substrate by an epitaxial growth method, so that the semiconductor layer having the high refractive index is formed on the semiconductor substrate. The semiconductor layer and the semiconductor layer having the low refractive index are sequentially and alternately stacked.

However, in the semiconductor distributed reflector forming method according to the present invention, when the semiconductor layer having the high refractive index is formed on the semiconductor substrate, the semiconductor layer is formed on the semiconductor substrate. The infrared rays radiated from the heating means through the semiconductor substrate and the semiconductor layer having a high refractive index being formed thereon are passed through a bandpass filter having a center wavelength equal to that of the semiconductor distributed reflector. The optical thickness of the semiconductor layer having a high refractive index being formed on the semiconductor substrate is detected from the intensity of the infrared ray having the center wavelength of the bandpass filter, and When a semiconductor layer having a low refractive index is being formed, infrared rays radiated from the substrate heating means through the semiconductor substrate and the semiconductor layer having a low refractive index being formed thereon are filtered through the bandpass filter. The optical thickness of the semiconductor layer having a low refractive index being formed on the semiconductor substrate is detected from the intensity of the infrared rays having the center wavelength of the bandpass filter obtained thereby, and the optical thickness of the semiconductor layer having a low refractive index being formed on the semiconductor substrate is detected. A detection output of the optical thickness of the semiconductor layer having a high refractive index that is being formed on the semiconductor substrate; a detection output of the optical thickness of the semiconductor layer having the low refractive index that is being formed on the semiconductor substrate; Based on this, molecules or atoms constituting the semiconductor forming the semiconductor layer having the high refractive index and molecules or atoms constituting the semiconductor forming the semiconductor layer having the low refractive index on the semiconductor substrate. Control the supply of sequential alternations with atoms.

The apparatus for forming a semiconductor distributed reflector according to the present invention, as in the case of the conventional apparatus for forming a semiconductor distributed reflector described above with reference to FIG. (iii) substrate heating means for heating the semiconductor substrate; and (iv) a semiconductor for forming a semiconductor layer having a high refractive index on the semiconductor substrate. The semiconductor layer having a high refractive index and the semiconductor layer having a low refractive index sequentially alternate the molecules or atoms forming the semiconductor layer forming the semiconductor layer having the high refractive index and the molecules or atoms forming the semiconductor forming the semiconductor layer having the low refractive index. A semiconductor distributed reflector is formed by laminating layers by an epitaxial growth method, thereby forming a semiconductor distributed reflector having a structure in which the semiconductor layer having a high refractive index and the semiconductor layer having a low refractive index are sequentially and alternately laminated. , a means for supplying semiconductor constituent molecules or atoms sequentially and alternately; (v) when the semiconductor layer having the high refractive index is being formed on the semiconductor substrate, the high refractive index that is being formed on the semiconductor substrate; When the semiconductor layer having the low refractive index is being formed on the semiconductor substrate, the optical thickness of the semiconductor layer having the low refractive index being formed on the semiconductor substrate is detected. (vi) an optical thickness detection means for detecting an optical thickness of a semiconductor layer having a high refractive index; and (vi) a semiconductor layer having a high refractive index that is being formed on the semiconductor substrate and is obtained from the optical thickness detection means. Based on the detection output of the optical thickness of the semiconductor layer and the detection output of the optical thickness of the semiconductor layer having a low refractive index that is being formed on the semiconductor substrate, the semiconductor constituent molecules or atoms supplying means A semiconductor for controlling the supply of molecules or atoms constituting a semiconductor forming a semiconductor layer having a high refractive index and molecules or atoms constituting a semiconductor forming a semiconductor layer having a low refractive index onto the semiconductor substrate. It has constituent molecules or atom supply control means.

However, in the apparatus for forming a semiconductor distributed reflector according to the present invention, in such an apparatus for forming a semiconductor distributed reflector, the optical thickness detecting means detects the thickness of the semiconductor substrate from the substrate heating means to the semiconductor substrate and the top thereof. an infrared rays emitting window provided in the vacuum container that guides the infrared rays radiated through the formed semiconductor layer to the outside of the vacuum container; an infrared detector arranged outside the vacuum container to be detected; an infrared optical path between the infrared ray extraction window and the infrared detector; and an infrared ray optical path arranged within the infrared optical path and the semiconductor distributed reflection mirror and a bandpass filter with equal center wavelength.

[0029]

[Operation/Effect] Method for forming a semiconductor distributed reflector according to the present invention,
According to the apparatus for forming a semiconductor distributed reflector used therein, molecules or atoms constituting a semiconductor forming a semiconductor layer having a high refractive index and a semiconductor forming a semiconductor layer having a low refractive index are placed on a semiconductor substrate. In order to control the sequential and alternating supply of the molecules or atoms constituting the semiconductor layer by the semiconductor constituting molecules or atoms supply control means, the optical thickness detection means A semiconductor substrate is heated to obtain a detection output representative of the thickness of the semiconductor layer and a detection output representative of the thickness of the semiconductor layer as it is forming a semiconductor layer having a low refractive index. Since the method utilizes infrared radiation obtained by radiating from the substrate heating means through the semiconductor substrate and the semiconductor layer being formed on the semiconductor substrate, the conventional semiconductor distribution described above in FIG. 4 can be used as the optical thickness detection means. Since there is no need to provide a means corresponding to the monochromatic beam irradiation means 60A in the case of the reflecting mirror forming device, even if a bandpass filter is required, the optical thickness detection means as described above in FIG. It can be made cheaper, simpler, and smaller than conventional devices for forming semiconductor distributed reflecting mirrors.

Furthermore, the optical thickness detection means outputs a detection output representing the thickness of a semiconductor layer having a high refractive index when the semiconductor layer is being formed, and a detection output representing the thickness of the semiconductor layer when the semiconductor layer having a low refractive index is being formed. In order to obtain a detection output representing the thickness of the semiconductor layer when the semiconductor layer is being formed, as described above, the semiconductor substrate and the semiconductor being formed thereon are obtained from the substrate heating means for heating the semiconductor substrate. The infrared rays obtained by radiation through the layer are utilized, and therefore the optical thickness detection means corresponds to the monochromatic light receiving means 60B in the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG. Even if it has a monochromatic light irradiation means 60 in the case of the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG.
On the other hand, the infrared rays obtained by radiating from the substrate heating means that heats the semiconductor substrate through the semiconductor substrate and the semiconductor layer that is being formed on the semiconductor substrate increase as the distance from the semiconductor substrate increases. Because it can be obtained by spreading, the conventional semiconductor distributed reflector forming apparatus described above in FIG. Since the fine adjustment required in the conventional semiconductor distribution reflector shown in FIG. This can be done more easily than in the case of a forming device.

Furthermore, for this reason, the optical thickness detection means is used to measure the optical thickness of each of the semiconductor layer having a high refractive index and the semiconductor layer having a low refractive index that are being formed on the semiconductor substrate. It is possible to detect the semiconductor distributed reflector with higher precision than the conventional device for forming a semiconductor distributed reflector described in 4. In addition, it is possible to form semiconductor distributed reflectors with higher precision than in the case of the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG. Can be easily formed. This means that in the optical thickness detection means, a bandpass filter having a center wavelength equal to that of the semiconductor distributed reflector to be formed is used, thereby detecting the center wavelength of the semiconductor distributed reflector to be formed in the infrared rays. This is especially true because the optical thickness of the semiconductor layer with a high refractive index and the semiconductor layer with a low refractive index being formed on the semiconductor substrate is detected by the intensity of the infrared rays.

[0032]

[Embodiment] Next, an embodiment of an apparatus for forming a semiconductor distributed reflecting mirror according to the present invention will be described with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted.

The apparatus for forming a semiconductor distributed reflector according to the present invention shown in FIG. 1 has the same structure as the conventional apparatus for forming a semiconductor distributed reflector shown in FIG. 4, except for the following points.

That is, instead of the conventional device for forming a semiconductor distributed reflector described above with reference to FIG. an infrared ray extraction window 81 provided in the vacuum container 10 for guiding the infrared rays UR radiated from the heater 41 of the substrate heating means 40 through the semiconductor substrate 20 and the semiconductor layer formed thereon to the outside of the vacuum container 10; An infrared detector 82 arranged outside the vacuum container 10 that detects infrared UR led out from inside the vacuum container 10 through the infrared leading window 81, and an infrared optical path between the infrared leading window 61 and the infrared detector 82. 83 and its infrared optical path 8
3. A semiconductor distributed reflector 21 to be formed and arranged in
It has a bandpass filter 64 having a center wavelength equal to
2, it is configured so that detection outputs DH and DL similar to those obtained by the monochromatic light detector 67 in the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG. 4 can be obtained.

The above is the configuration of the embodiment of the apparatus for forming a semiconductor distributed reflecting mirror according to the present invention. Next, an embodiment of the method for forming a semiconductor distributed reflector according to the present invention using the apparatus for forming a semiconductor distributed reflector according to the present invention shown in FIG. 1 will be described.

In the embodiment of the method for forming a semiconductor distributed reflector according to the present invention, a means 6 for supplying molecules or atoms onto a semiconductor substrate 20 is used.
Molecular beam BH from molecular beam source 51A constituting 0;
Control of the sequential and alternating supply of the molecular beam BL from the molecular beam source 51B, and therefore the molecules constituting the semiconductor forming the semiconductor layer 22H having a high refractive index and the semiconductor forming the semiconductor layer 22L having a high refractive index. This is the same as in the case of the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG. 4, except that the sequential and alternating supply of the molecules constituting the molecule is controlled as described below.

That is, the semiconductor layer 22 having a high refractive index
When forming H, the heater 41 of the substrate heating means 40
The infrared rays UR radiated from the semiconductor substrate 20 and the semiconductor layer 22H having a high refractive index that is being formed on the semiconductor substrate 20 are transmitted through the infrared rays emitting window 81 of the vacuum container 10 constituting the optical thickness detecting means 60. A band-pass filter 84 constituting the optical thickness detection means 60 having a center wavelength λ equal to that of the semiconductor distributed reflector 21 to be formed.
The intensity of the infrared UR having the center wavelength λ of the bandpass filter 84 obtained thereby is detected by the infrared detector 84 constituting the optical thickness detecting means 60, and therefore, from the infrared detector 84, When the detection output DH representing the optical thickness of the semiconductor layer 22H having a high refractive index being formed on the semiconductor substrate 20 is obtained, and when the semiconductor layer 22L having a low refractive index is being formed, the substrate The optical thickness detection means 6 detects infrared rays UR radiated from the heater 41 of the heating means 40 through the semiconductor substrate 20 and the semiconductor layer 22L having a low refractive index that is being formed on the semiconductor substrate 20.
0, through the infrared light emitting window 81 of the vacuum vessel 10, forming the optical thickness detection means 60, which has a center wavelength λ equal to that of the semiconductor distributed reflector 21 to be formed. The intensity of the infrared rays UR having the center wavelength λ of the bandpass filter 84 obtained thereby is detected by the infrared detector 84 constituting the optical thickness detecting means 60. , a detection output DL representing the optical thickness of the semiconductor layer 22L having a low refractive index being formed on the semiconductor substrate 20 is obtained, and these detection outputs DH and DL are controlled to supply semiconductor constituent molecules or atoms. The signal is supplied to a control/drive circuit 71 constituting the means 70, and the control/drive circuit 71 controls the opening and closing of the shutters 52H and 52L in an inverse relationship to each other.

The above is an embodiment of the method for forming a semiconductor distributed reflector according to the present invention using the apparatus for forming a semiconductor distributed reflector according to the present invention shown in FIG.

The embodiments of the method for forming a semiconductor distributed reflector according to the present invention and the embodiments of the apparatus for forming a semiconductor distributed reflector according to the present invention used therefor have been clarified above.

According to the embodiment of the method for forming a semiconductor distributed reflector according to the present invention and the apparatus for forming a semiconductor distributed reflector according to the present invention used therein, it is clear from the above, and detailed explanation will be omitted. When a semiconductor layer 22H having a high refractive index and a semiconductor layer 22L having a low refractive index are formed separately on the semiconductor layer 22H, the semiconductor layer 22H has a high refractive index.
and optical thickness detection means 6 for each separate thickness of 22L.
As shown in FIG. Since the minimum value and maximum value are taken sequentially at intervals of /4, a high refractive index is The semiconductor layer 22H having a low refractive index and the semiconductor layer 22L having a low refractive index can be easily formed in a thickness that is 1/4 of the center wavelength of the semiconductor distributed reflector 21 to be formed in sequence and alternately. A semiconductor distributed reflector 21 having a center wavelength λ can be formed on the semiconductor substrate 20, in which semiconductor layers 22H having a high refractive index and semiconductor layers 22L having a low refractive index are sequentially and alternately laminated.

However, according to the embodiment of the semiconductor distributed reflector forming method according to the present invention and the embodiment of the semiconductor distributed reflector forming apparatus used therein, the semiconductor layer 22H having a high refractive index is formed on the semiconductor substrate 20. In order to control the sequential and alternate supply of molecules constituting the semiconductor forming the semiconductor layer 22L having a low refractive index and molecules constituting the semiconductor forming the semiconductor layer 22L having a low refractive index, the semiconductor constituting molecule or atom supply control means 70 uses an optical The target thickness detecting means 60 outputs a detection output DH representing the thickness of the semiconductor layer 22H when the semiconductor layer 22H having a high refractive index is being formed and a semiconductor layer 22L having a low refractive index. In order to obtain the detection output DL representing the thickness of the semiconductor layer 22L when the semiconductor substrate 22L is being formed, the semiconductor substrate 20 and the semiconductor layer 22L being formed as described above are transmitted from the substrate heating means 40 for heating the semiconductor substrate 20. Since the infrared rays obtained by radiating through the UR are used, the optical thickness detection means 60 corresponds to the monochromatic light irradiation means 60A in the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG. Therefore, even if the bandpass filter 84 is required, the optical thickness detection means 60 can be provided at a lower cost than in the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG. , it can be made simple and compact.

[0042] Furthermore, the optical thickness detecting means 60
Detection output DH representing the thickness of the semiconductor layer 22H when the semiconductor layer 22H having a high refractive index is being formed
As described above, in order to obtain the detection output DL representing the thickness of the semiconductor layer 22L when the semiconductor layer 22L having a low refractive index is being formed, The optical thickness detecting means 60 utilizes infrared rays obtained by radiation from the substrate heating means 40 through the semiconductor substrate 20 and the semiconductor layer being formed thereon, and therefore the optical thickness detecting means 60 is similar to the conventional semiconductor device described above in FIG. Even if it has a means corresponding to the monochromatic light receiving means 60B in the case of the distributed reflecting mirror forming apparatus, the monochromatic light irradiating means 60A in the case of the conventional semiconductor distributed reflecting mirror forming apparatus described above with reference to FIG. On the other hand, infrared rays obtained by radiating from the substrate heating means 40 that heats the semiconductor substrate 20 through the semiconductor substrate 20 and the semiconductor layer being formed on the semiconductor substrate 20 side, the conventional method described above with reference to FIG. Since the fine adjustment required in the case of the semiconductor distributed reflector forming apparatus is not required, these substrate mounting stages 31
Setting the orientation of the semiconductor substrate and placing the semiconductor substrate on the substrate mounting table 31 can be performed more easily than in the case of the conventional semiconductor distributed reflector forming apparatus described above with reference to FIG.

Furthermore, for this reason, the optical thickness detection means 6
0, the respective optical thicknesses of the semiconductor layer 22H having a high refractive index and the semiconductor layer 22L having a low refractive index, which are being formed on the semiconductor substrate 20, are calculated using the conventional semiconductor distributed reflector described above with reference to FIG. It is possible to detect the semiconductor layer 22H having a high refractive index and the semiconductor layer 22L having a low refractive index at the desired λ.
/4 thickness, and can be formed with higher precision than in the case of the conventional semiconductor distributed reflector forming apparatus described above in FIG.
Therefore, the semiconductor distributed reflector 21 can be easily formed to have a desired highly accurate center wavelength λ. This means that in the optical thickness detection means 60, a bandpass filter 84 having a center wavelength λ equal to that of the semiconductor distributed reflector 21 to be formed is used.
With the intensity of infrared rays having the center wavelength λ of the semiconductor distributed reflector 21 to be formed in R, the semiconductor layer 22H having a high refractive index and the semiconductor layer 22L having a low refractive index being formed on the semiconductor substrate 20 are This is especially true since each individual optical thickness is detected.

From the above, according to the method of forming a semiconductor distributed reflector according to the present invention and the apparatus for forming a semiconductor distributed reflector used therein, the method shown in FIG. 3, in which the corresponding parts to those in FIG. A light emitting section 25 in which a semiconductor layer 23 as an active layer and a semiconductor layer 24 as a well layer are alternately stacked on a semiconductor substrate 20 such as two 22N
and 22P are the semiconductor distributed reflector 22N and the light emitting section 25.
and the semiconductor distributed reflector 22P, and an electrode 26 is attached to the opposite side of the semiconductor substrate 20 from the semiconductor distributed reflector 22N side, and an electrode 26 is formed on the semiconductor distributed reflector 22P via the semiconductor layer 28 for electrode attachment. This method is suitable for manufacturing a planar multi-quantum well semiconductor laser in which an electrode 27 is attached.

In the planar multi-quantum well semiconductor laser shown in FIG. 3, the semiconductor substrate 20 has N type and is made of InP, and the semiconductor distributed reflectors 22N and 22P have n type and p type, respectively. Furthermore, the semiconductor layer 22H having a high refractive index and the semiconductor layer 22L having a low refractive index therein are made of InGaAsP and InP, respectively, and the semiconductor layer 23 as an active layer and the well layer in the light emitting part 25 are The semiconductor layers 24 are each made of InG.
The semiconductor layer 28 may be made of aAsP type or InGaAs type, and the electrode-attached semiconductor layer 28 may be p-type and made of InP. Furthermore, it is clear that the semiconductor layers 23 and 24 of the light emitting section 25 can also be formed according to the present invention.

Further, in the above description, the case has been described in which the molecule or atom supply means 50 is configured such that the semiconductor layers 22H and 22L are formed by the molecular beam epitaxial growth method. Layers 22H and 22L are formed by gas source MBE method, MOCVD
It may be configured such that it is formed by a law or the like, and various other modifications and changes may be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 illustrates a method for forming a semiconductor distributed reflector according to the present invention and an apparatus for forming a semiconductor distributed reflector used therein.
1 is a schematic cross-sectional view showing an embodiment of an apparatus for forming a semiconductor distributed reflector according to the present invention.

FIG. 2 is a diagram showing changes in the intensity of infrared rays with respect to the thickness of a semiconductor layer when the semiconductor layer is formed on a semiconductor substrate.

[Figure 3]

FIG. 1 is a schematic cross-sectional view showing a semiconductor laser having a semiconductor distributed reflector manufactured by the semiconductor distributed reflector forming method according to the present invention using the semiconductor distributed reflector forming apparatus according to the present invention shown in FIG. be.

FIG. 4 is a schematic cross-sectional view showing a conventional semiconductor distributed reflector forming apparatus for explaining a conventional semiconductor distributed reflector forming method and a semiconductor distributed reflector forming apparatus used therein.

[Explanation of symbols]

10 Vacuum container 20
Semiconductor substrate 22H
Semiconductor layer 22L with high refractive index
Semiconductor layer 21 with low refractive index
Semiconductor distributed reflector 30
Substrate mounting means 31
Board mounting table 32
Substrate mounting surface 40 Substrate heating means 41 Heater 5
0 Semiconductor constituent molecules or atoms supply means 51 Molecular beam generation sources 51H, 51L Shutter 60 Optical thickness detection means 60A Monochromatic light irradiation means 60
B Monochromatic light receiving means 61
Monochromatic light source 62
Monochromatic light introduction window 63
Optical path 66 for monochromatic light
Monochromatic ray extraction window 67
Monochromatic ray detector 68
Optical path 69 for monochromatic rays
Optical lens 70 Semiconductor constituent molecules or atom supply control means

Claims (2)

[Claims] 1. Molecules or atoms constituting a semiconductor forming a semiconductor layer having a high refractive index and semiconductor forming a semiconductor layer having a low refractive index are formed on a semiconductor substrate heated by a substrate heating means. By sequentially and alternately supplying molecules or atoms to the semiconductor substrate,
The semiconductor layer having the high refractive index and the semiconductor layer having the low refractive index are sequentially and alternately stacked by an epitaxial growth method, so that the semiconductor layer having the high refractive index and the semiconductor layer having the low refractive index are formed on the semiconductor substrate. In the method of forming a semiconductor distributed reflector having a structure in which semiconductor layers having a certain ratio are sequentially and alternately stacked, on the semiconductor substrate,
When forming the semiconductor layer having a high refractive index, the infrared rays radiated from the substrate heating means through the semiconductor substrate and the semiconductor layer having a high refractive index being formed thereon are reflected by the semiconductor in a distributed manner. The intensity of the infrared rays having the center wavelength of the bandpass filter obtained by passing the infrared rays through a bandpass filter having a center wavelength equal to that of the mirror allows the semiconductor layer having a high refractive index being formed on the semiconductor substrate to be detected. The optical thickness is detected, and when the semiconductor layer having the low refractive index is being formed on the semiconductor substrate, the semiconductor layer and the low refractive index being formed on the semiconductor substrate are detected from the substrate heating means. The infrared rays radiated through the semiconductor layer having the same wavelength are passed through the bandpass filter, and from the intensity of the resulting infrared rays having the center wavelength of the bandpass filter, the low refraction that is being formed on the semiconductor substrate is detected. detecting an optical thickness of a semiconductor layer having a high refractive index, and outputting a detection output of an optical thickness of a semiconductor layer having a high refractive index that is being formed on the semiconductor substrate; Based on the detection output of the optical thickness of the semiconductor layer having a low refractive index, molecules or atoms constituting the semiconductor forming the semiconductor layer having a high refractive index on the semiconductor substrate; A method for forming a semiconductor distributed reflector, characterized in that the sequential and alternate supply of molecules or atoms constituting the semiconductor forming the semiconductor layer having a low refractive index is controlled. 2. A vacuum container, a substrate mounting means disposed in the vacuum container and on which a semiconductor substrate is placed, a substrate heating means for heating the semiconductor substrate, and a high refractive index material on the semiconductor substrate. Molecules or atoms constituting a semiconductor forming a semiconductor layer having a high refractive index and molecules or atoms constituting a semiconductor forming a semiconductor layer having a low refractive index are combined into a semiconductor layer having a high refractive index and a semiconductor layer having a low refractive index. A semiconductor distribution having a structure in which semiconductor layers having a high refractive index and semiconductor layers having a low refractive index are sequentially and alternately laminated by an epitaxial growth method. so that a reflective mirror is formed,
A means for supplying semiconductor constituent molecules or atoms sequentially and alternately, and when the semiconductor layer having the high refractive index is being formed on the semiconductor substrate, the semiconductor having the high refractive index that is being formed on the semiconductor substrate. In addition to detecting the optical thickness of the layer, when the semiconductor layer having the low refractive index is being formed on the semiconductor substrate, the optical thickness of the semiconductor layer having the low refractive index being formed on the semiconductor substrate is detected. an optical thickness detection means for detecting optical thickness; and detection of the optical thickness of the semiconductor layer having a high refractive index that is being formed on the semiconductor substrate, obtained from the optical thickness detection means. Based on the output and the detection output of the optical thickness of the semiconductor layer having a low refractive index that is being formed on the semiconductor substrate, the semiconductor constituent molecules or atoms supply means:
A semiconductor constituent molecule that controls the supply of molecules or atoms constituting a semiconductor forming a semiconductor layer having a high refractive index and molecules or atoms constituting a semiconductor forming a semiconductor layer having a low refractive index onto the semiconductor substrate. In the apparatus for forming a semiconductor distributed reflector having an atom supply control means, the optical thickness detection means detects infrared rays radiated from the substrate heating means through the semiconductor substrate and the semiconductor layer formed thereon. an infrared light emitting window provided in the vacuum container that is guided out of the vacuum container; and an infrared light disposed outside the vacuum container that detects the infrared light emitted from inside the vacuum container through the infrared light emitting window. a detector, an infrared optical path between the infrared light emitting window and the infrared detector, and a bandpass filter disposed within the infrared optical path and having a center wavelength equal to that of the semiconductor distributed reflector; 1. An apparatus for forming a semiconductor distributed reflector, comprising: