A molecular beam epitaxial growth control method and source furnace device

Abstract

The present invention discloses a molecular beam epitaxy growth control method and a source furnace device. The molecular beam epitaxy growth material includes determining elements and excess elements. The determining elements are elements whose beam flow directly affects the growth rate and / or composition, and the excess elements are elements whose beam flow does not affect the growth rate and / or composition after exceeding a certain value. A growth source furnace and a compensation source furnace are set for each determining element. The growth source furnace is temperature-controlled according to an empirical curve and keeps the temperature stable during the growth process of each furnace. The compensation source furnace has a variable temperature during the growth process of each furnace. The difference between the actual growth rate or beam current of the growth source furnace and the target growth rate or beam current is compensated by adjusting the temperature of the compensation source furnace. The source furnace device includes a growth source furnace and a compensation source furnace, which are used to implement the above method. The present invention can adjust the growth rate or beam current more accurately and controllably without increasing the temperature control accuracy of the source furnace.

Description

Technical Field

[0001] The invention relates to the technical field of molecular beam epitaxial growth control, and in particular to a molecular beam epitaxial growth control method and a source furnace device. Background Art

[0002] The conventional growth control method in molecular beam epitaxy growth is to measure the beam current through the growth gap, or to perform XRD scanning on the grown sample and fit to determine the growth rate and composition, and then adjust the temperature of the corresponding source furnace to control the growth rate and composition within the required range. This adjustment method is more suitable for structures with simple structures, few epitaxial layers, and short growth time. However, if the growing structure is complex, the number of epitaxial layers is large, and the growth time is long, it is difficult to use the above control method. On the one hand, these structures have a long growth time, and the growth of a single structure may take 6-14 hours. Although the temperature of the source furnace remains unchanged during this period, the beam current is reduced to a certain extent, resulting in the growth only in the growth gap. Testing and adjusting the source furnace is difficult to meet the requirements of the composition and thickness of the entire structure, especially for some structures with strict requirements on thickness and composition, such as vertical cavity surface lasers (VCSELs), resonant cavity enhanced photodetectors (RCEPDs), quantum well infrared detectors (QWIPs), etc. On the other hand, the XRD spectra of complex structures with many epitaxial layers are complex and difficult to accurately fit and calculate, which may lead to inaccurate adjustment of the source furnace.

[0003] At present, many literatures have proposed in-situ monitoring and control methods for this type of multilayer structure, such as in-situ beam measurement using infrared oscillation spectroscopy, reflection spectroscopy, and atomic absorption spectroscopy. After in-situ monitoring finds that the growth rate or beam current provided by the source furnace deviates from the design value, the usual adjustment method is to adjust the shutter switch time, or simply adjust the temperature of the source furnace. Adjusting the shutter switch time can easily control the growth thickness, but it is difficult to adjust the composition of the multi-element alloy because the drift amount of different source furnaces may be different. And simply controlling the temperature of the source furnace is also difficult in terms of accuracy. The temperature of the source furnace and the beam current / growth rate are positively correlated, but not linearly. The higher the temperature of the source furnace, the greater the effect of adjusting the same temperature difference on the beam current / growth rate. The growth rate of multilayer structures is usually not very slow, and the temperature of the source furnace is usually high. At this time, if the growth rate needs to be accurately adjusted during growth, it means that the source furnace needs to adjust a very small temperature. This small temperature adjustment is a great challenge for both thermocouples and voltage power control. Summary of the invention

[0004] The purpose of the present invention is to provide a molecular beam epitaxial growth control method and source furnace device, which adopts a low-temperature compensation source furnace to make adjustments during the growth process, so that the growth rate or beam current can be adjusted more accurately and controllably without improving the temperature control accuracy of the source furnace.

[0005] The technical solution of the present invention is described in detail as follows:

[0006] In a first aspect, the present invention provides a molecular beam epitaxial growth control method, wherein the molecular beam epitaxial growth material includes a determining element and an excess element, wherein the determining element is an element whose beam flow directly affects the growth rate and / or composition, and the excess element is an element whose beam flow does not affect the growth rate and / or composition after exceeding a certain value;

[0007] A growth source furnace and a compensation source furnace are set for each determining element. The temperature of the growth source furnace is controlled according to an empirical curve and the temperature is kept stable during each furnace growth process. The temperature of the compensation source furnace is variable during each furnace growth process. The difference between the actual growth rate or beam current of the growth source furnace and the target growth rate or beam current is compensated by adjusting the temperature of the compensation source furnace.

[0008] In the above method, the excess element does not require two source furnaces. After the beam current or growth rate exceeds a certain value (which can be obtained from previous experiments), the growth rate or beam current and composition are determined by the beam current of other determining elements and have nothing to do with this element.

[0009] For the determining element, an empirical curve of "temperature-beam current" is usually made before the formal growth. This empirical curve gives the relationship between the source furnace temperature and the beam current. At the same time, it is generally believed that the beam current and the growth rate are in a simple proportional relationship. Therefore, the empirical curve of "temperature-beam current" and the single "beam current-growth rate" relationship can be used to obtain the empirical curve of "temperature-growth rate".

[0010] The source furnace of the growth source furnace has a high temperature and provides a large beam current, which can provide most of the required growth rates and keep the temperature stable during each furnace growth process. The source furnace of the compensation source furnace has a low temperature and provides a small beam current, which is used to compensate for the difference between the growth rate or beam current provided by the growth source furnace and the growth rate or beam current design value, and the temperature can be changed during each furnace growth to compensate for the growth rate or beam current attenuation of the growth source furnace during growth.

[0011] In the above method, before the growth starts, the source furnace temperature of the growth source furnace can be stabilized at the starting temperature obtained according to the empirical curve of the growth source furnace, and the growth source furnace provides a certain growth rate or beam current. The source furnace temperature of the compensation source furnace is stabilized at the compensation starting temperature obtained according to the empirical curve of the compensation source furnace. At this time, the compensation source furnace can provide another part of the growth rate or beam current. The sum of the growth rate or beam current provided by the growth source furnace and the growth rate or beam current provided by the compensation source furnace is the target growth rate or beam current of the determining element. During the growth process, the temperature of the growth source furnace remains unchanged. As the growth time increases, the growth source furnace and the compensation source furnace will produce a decrease in growth rate or beam current attenuation, and the total growth rate or beam current will also decrease. At this time, the traditional in-situ monitoring method can be used to monitor the changes in the growth thickness, composition or beam current. When the total growth rate or beam current is monitored to be reduced to a certain value, it is necessary to increase the temperature of the compensation source furnace so that the compensation source furnace provides more growth rate or beam current, so that the total growth rate or beam current of the determining element returns to the design value or design range. If there are multiple determining elements, each determining element can be adjusted separately.

[0012] Optionally or preferably, in the above method, the growth rate or beam current provided by the growth source furnace accounts for 80% to 95% of the total rate or beam current.

[0013] The growth source furnace can use a large crucible and source furnace to hold more source materials. Its temperature is PID controlled, and the PID parameters are selected to have good stability and general followability. The compensation source furnace can use a small crucible and source furnace to hold less source materials. Its temperature is PID controlled, and the PID parameters are selected to have good followability and general stability.

[0014] Optionally or preferably, in the above method, in the interval between two growths, the temperatures of the growth source furnace and the compensation source furnace are adjusted by the following (1) or (2):

[0015] (1) The temperature of the compensation source furnace drops to the state before the growth begins, and the temperature of the growth source furnace is raised;

[0016] (2) Maintain the temperature of the growth source furnace and the compensation source furnace at the end of the previous growth and proceed directly to the next growth.

[0017] After a growth cycle is completed, the temperatures of the growth source furnace and the compensation source furnace can be adjusted using the above method (1) or (2) according to actual conditions.

[0018] Method (1) Cooling the compensation source furnace to the state before the start of growth means cooling it to the temperature before the start of this growth, or to the growth rate or beam current value before the start of growth. The purpose of heating the growth source furnace is to make the sum of the growth rate or beam current provided by the growth source furnace and the growth rate or beam current provided by the compensation source furnace equal to the target growth rate or target beam current of the element.

[0019] After one growth, if the temperature of the compensation source furnace after growth is not much higher than the temperature before growth, the growth rate or beam current provided by the compensation source furnace is still low, and it can be predicted that the growth rate or beam current provided by the compensation source furnace will still be at a low level after the next growth, then method (2) can be applied to maintain the temperature of the growth source furnace and the compensation source furnace at the end of this growth, and directly carry out the next growth. In the next growth, the temperature of the growth source furnace is still kept unchanged, and the growth rate or beam current of the element is maintained by gradually increasing the temperature of the compensation source furnace. In this way, more growth can be continued until it is expected that the growth rate or beam current value provided by the compensation source furnace exceeds a certain proportion at the end of the next growth. At this time, the growth rate or beam current provided by the compensation source furnace is too high, and the corresponding temperature of the compensation source furnace is also in a high range. A small change in the temperature of the compensation source furnace will cause a large change in the growth rate or beam current, which is not conducive to continued fine adjustment. At this time, according to the operation of method (1), the compensation source furnace is cooled down to the temperature before the continuous heating, or the growth rate or beam current value before the continuous heating. At the same time, the growth source furnace is heated up so that the sum of the growth rate or beam current provided by the growth source furnace and the growth rate or beam current provided by the compensation source furnace is the target growth rate or target beam current of the element.

[0020] Optionally or preferably, in the above method, when it is estimated that at the end of the next growth, the percentage of the growth rate or beam current provided by the compensation source furnace to the total growth rate or beam current exceeds a set value, method (1) is used to adjust the temperature of the growth source furnace and the compensation source furnace.

[0021] Optionally or preferably, in the above method, the set value is a value between 10% and 20%.

[0022] Optionally or preferably, in any of the above methods, when it is monitored that the total growth rate or beam current deviates from a preset value by 0.5% to 1.0%, the compensation source furnace temperature is adjusted.

[0023] Optionally or preferably, in any of the above methods, when it is monitored that the optical thickness deviation of the molecular beam epitaxial growth product is above 0.5%, the compensation source furnace temperature is adjusted.

[0024] Optionally or preferably, in any of the above methods, the temperature change rate of the compensation source furnace is 0.1°C / min to 0.5°C / min. This range can avoid temperature overshoot and beam fluctuation caused by power change during rapid temperature rise. In this way, the growth rate and beam stability can be maintained, and misjudgment of the adjustment result caused by growth rate or beam fluctuation in a short period of time can be avoided.

[0025] In a second aspect, the present invention provides a source furnace device for molecular beam epitaxial growth, including a growth source furnace and a compensation source furnace, for implementing any of the molecular beam epitaxial growth control methods described above.

[0026] The method and apparatus of the present invention are applicable to the growth of various semiconductor materials. For example, in the growth of GaAs, AlAs or AlGaAs, Ga and Al are the determining elements and As is an excess element. Similarly, when InGaAs and InAlAs are grown, In and Ga, In and Al are the determining elements and As is an excess element. When InP and InGaP are grown, In, In and Ga are the determining elements and P is an excess element. When InSb, InGaSb and InAlSb are grown, In, In and Ga, In and Al are the determining elements and Sb is an excess element. When growing II-VI group materials, usually the II group elements are the determining elements, such as Zn, Cd, etc., and the VI group elements are the excess elements, such as Se, Te, etc.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] Compared with the previous method of using the baffle switch time to control the growth thickness, the control method of the present invention can not only adjust the growth rate, maintain the growth thickness, and reduce the time compensation caused by the decrease in growth rate, but also accurately control the alloy composition through independent adjustment of different element source furnaces.

[0029] Compared with the previous method of adjusting the element growth rate by adjusting the source furnace temperature, the present invention utilizes the characteristic of the source furnace in the low temperature range that the adjustment of the trace growth rate or beam current corresponds to a large temperature adjustment amount, and adopts a low-temperature compensation source furnace to make adjustments during the growth process. In this way, the growth rate or beam current can be adjusted more accurately and controllably without improving the temperature control accuracy of the source furnace.

[0030] If the compensation source furnace uses a source furnace with a small volume and less source material, its growth rate or beam current will respond quickly to temperature changes, so that the deviation of the growth rate can be quickly corrected, and after adjustment, it can be quickly confirmed by monitoring whether the adjustment is appropriate, effectively avoiding the situation where the response is delayed and it is necessary to rely on experience values ​​to a large extent, or it is difficult to judge the adjustment effect. In addition, when selecting PID parameters, it is difficult to achieve very good results in stability and followability at the same time, and usually only one of them can be adjusted to the optimal value. In the present invention, the compensation source furnace preferably has very good followability PID parameters. Although a small amount of stability is sacrificed, due to the low operating temperature of the compensation source furnace, the temperature fluctuation corresponds to a relatively small growth rate or beam current fluctuation, and the main growth rate or beam current is provided by the growth source furnace. Therefore, even if a small amount of temperature stability is sacrificed, the stability of the total growth rate or beam current can still be maintained. The growth source furnace is large in volume and has a lot of source materials. The PID parameter selection sacrifices part of the followability and focuses on stability, which is also very beneficial to the stability of the total growth rate. The temperature change of the growth source furnace is carried out between two growths, so the requirement for the temperature followability of the source furnace itself is not high.

[0031] In the control method of the present invention, if multiple determining elements are involved in the growth, the parameters and adjustments of each element can be relatively independent. For the above parameters, such as the growth rate or beam current ratio occupied by the growth source furnace, the growth rate or beam current deviation value when adjustment is required, the growth rate or beam current upper limit that can be achieved by the compensation source furnace, the source furnace temperature change rate, etc., each determining element can choose the same or different values ​​according to the growth needs. When adjusting the source furnace temperature, it is also possible to adjust one source furnace individually or several source furnaces at the same time. The adjustment method is flexible and changeable. In general, for convenience, and considering that when the growth rate or beam current of an element decreases, other elements usually also have a certain degree of growth rate or beam current decrease. In order to ensure the stability of the compound components, when one determining element reaches the point where the source furnace temperature needs to be adjusted, the source furnace temperature of other determining elements will also be calculated and adjusted synchronously. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : Schematic diagram of the growth rate of a certain determining element and the change of source furnace temperature in specific embodiment 1.

[0033] Figure 2 : Schematic diagram of the growth rate of a certain determining element and the change of source furnace temperature in specific embodiment 2. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the present application, the present application will be described clearly and completely below in conjunction with the embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0035] Example 1

[0036] In the growth of GaAs-AlGaAs VCSEL structure. The determining elements are Ga and Al, and the excess element is As. The source furnace adjustment method is shown in the attached Figure 1 .

[0037] Two Ga furnaces and two Al furnaces are used. The growth source furnace in the Ga furnace is numbered Ga1, and the compensation source furnace in the Ga furnace is numbered Ga2. The growth source furnace in the Al furnace is numbered Al1, and the compensation source furnace in the Al furnace is numbered Al2.

[0038] Before growth, use a beam meter or calibration structure to adjust the temperature of the Ga1 and Ga2 source furnaces so that the total growth rate reaches the target growth rate R0(Ga). At the same time, the growth rate R1(Ga) of Ga1 accounts for 90%~93% of the total growth rate R0(Ga), and the growth rate r1(Ga) of Ga2 accounts for 7-10% of the total growth rate R0(Ga). At this time, the temperatures of Ga1 and Ga2 are T1(Ga) and t1(Ga), respectively. Similarly, calibrate the total growth rate of Al1 and Al2 to the target value R0(Al). Among them, the growth rate R1(Al) of Al1 accounts for 90%~93% of the total growth rate R0(Al), and the growth rate r1(Al) of Al2 accounts for 7-10% of the total growth rate R0(Al). At this time, the temperatures of Al1 and Al2 are T1(Al) and t1(Al), respectively.

[0039] During the growth, the temperature of stable Ga1 is T1(Ga), and the temperature of stable Al1 is T1(Al). Interference and amplitude monitoring techniques are used for in-situ measurement and compared with the simulation curve (which can be considered as the curve calculated theoretically) to monitor the optical thickness and composition deviation.

[0040] When the optical thickness deviation reaches 0.5%~0.7%, adjustment intervention begins. Since the optical thickness is related to the actual thickness and refractive index, and the refractive index is related to the composition. Therefore, the actual thickness measured value is first calculated based on the optical thickness measurement value and the composition measurement value. Then, the current total rate R(Ga) of Ga and the total rate R(Al) of Al are calculated based on the thickness measurement value, the composition measurement value and the baffle switching time, and compared with the target growth rate R0(Ga) of Ga and the target growth rate R0(Al) of Al to obtain the difference. On this basis, according to the "temperature-rate" empirical curve relationship of the compensation source furnace Ga2 and / or Al2, the temperature Δt(Ga) and / or Δt(Al) that Ga2 and / or Al2 need to be increased is calculated. Then, according to a slower temperature change rate, such as 0.2℃ / min, Ga2 and / or Al2 are changed to the target temperature t2(Ga) and / or t2(Al). The above-mentioned temperature adjustment of Ga and Al can be carried out simultaneously or independently according to the actual deviation situation. Continue to monitor the thickness and composition to confirm whether the adjustment is appropriate and whether the temperature of the compensation source furnace Ga2 and / or Al2 needs to be increased again over time to compensate for the growth rate drift of Ga and / or Al during the growth process until the growth is completed.

[0041] At the end of this growth, Ga2 is heated to t2(Ga), and Al2 is heated to t2(Al). Before the next growth, the temperature of the compensation source furnaces Ga2 and Al2 is returned to the starting temperature t1(Ga) and t1(Al) of this growth. At the same time, according to the beam current or calibration structure, the growth source furnaces Ga1 and Al1 are heated to T2(Ga) and T2(Al), so that the total growth rate of Ga1 and Ga2 reaches the set value R0(Ga), and the total growth rate of Al1 and Al2 reaches the set value R0(Al). Then the next growth is carried out.

[0042] Example 2

[0043] Grow GaAs-AlGaAs-InGaAs QWIP structure. The determining elements are Ga, Al and In, and the excess element is As. See the attached source furnace adjustment method. Figure 2 .

[0044] Each element of Ga, Al, and In in the equipment has two source furnaces. One group of Ga, Al, and In source furnaces is a growth source furnace, numbered Ga1, Al1, and In1, with a large crucible, which contains more source materials, and the PID setting is good for stability. The other group of Ga, Al, and In source furnaces is a compensation source furnace, numbered Ga2, Al2, and In2, with a small crucible, which contains less source materials, and the PID setting is good for followability. The weight of the source material contained in the growth source furnace is 5-10 times that of the compensation source furnace.

[0045] Before growth, adjust the temperature of Ga1 and Ga2 source furnaces so that the total Ga beam current reaches the target beam current F0(Ga). At the same time, the beam current F1(Ga) of Ga1 accounts for 90% of the total beam current F0(Ga), and the beam current f1(Ga) of Ga2 accounts for 10% of the total beam current F0(Ga). At this time, the temperatures of Ga1 and Ga2 are T1(Ga) and t1(Ga), respectively. Similarly, calibrate the total beam current of Al1 and Al2 to the target value F0(Al). Among them, the beam current F1(Al) of Al1 accounts for 90% of the total beam current F0(Al), and the beam current f1(Al) of Al2 accounts for 10% of the total beam current F0(Al). At this time, the temperatures of Al1 and Al2 are T1(Al) and t1(Al), respectively. Calibrate the total beam current of In1 and In2 to the target value F0(In). The beam current F1(In) of In1 accounts for 90% of the total beam current F0(In), and the beam current f1(In) of In2 accounts for 10% of the total beam current F0(In). At this time, the temperatures of In1 and In2 are T1(In) and t1(In) respectively.

[0046] During the growth, the temperature of Ga1, Al1, and In1 is stabilized. The temperature and power control are controlled by using the PID parameters with good stability, which can ensure that the temperature fluctuation of Ga1, Al1, and In1 is within ±0.05℃ and the power fluctuation is within ±0.5%. At the same time, the atomic absorption spectrometer is used to measure the in-situ beam current of the three elements.

[0047] When the deviation between the in-situ beam current measurement value of an element and the target value reaches 0.6-0.8%, adjustment intervention begins. Take Ga as an example. When the total Ga beam current F(Ga) is reduced to 99.2-99.4% of the target Ga beam current F0(Ga), the temperature that Ga2 needs to be increased is calculated based on the "temperature-beam current" empirical curve of the Ga compensation source furnace Ga2, and then Ga2 is heated to the target temperature t2(Ga) at a slower temperature change rate, such as 0.1-0.3℃ / min. Since the compensation source furnace Ga2 uses PID parameters with good followability, the difference between the actual temperature and the set temperature during the entire temperature change process is less than 0.1℃. Continue to monitor the in-situ beam current to confirm whether the adjustment is appropriate and whether the temperature of the compensation source furnace Ga2 needs to be increased again over time to compensate for the beam drift of Ga during the growth process until the growth is completed. In the same way, the temperatures of the Al and In compensation source furnaces Al2 and In2 are gradually increased to keep the measured beam current values ​​of Al and In within the target beam current range. When the growth is finished, the temperatures of the Ga, Al, and In compensation source furnaces are raised to t2(Ga), t2(Al), and t2(In), respectively.

[0048] After the current growth is completed, the beam current proportion of the compensation source furnace at the end of the next furnace is estimated based on the beam current proportion of the compensation source furnace at the beginning and end of this growth. If the estimated result is that the beam current proportion of the compensation source furnace at the end of the next furnace is still no more than 17%, the temperatures of all growth source furnaces and compensation source furnaces remain unchanged, and the next growth is directly entered. And in the next growth, the compensation source furnace will continue to be gradually heated up in the same way as in this growth for compensation. After one growth, the temperature of the Ga, Al, and In compensation source furnaces will continue to rise to t3 (Ga), t3 (Al), and t3 (In). If growth can continue, the temperature of the Ga, Al, and In compensation source furnaces will continue to rise to t4 (Ga), t4 (Al), and t4 (In), and so on.

[0049] For example, after three growths, it is estimated that the beam current ratio of a compensation source furnace will exceed 17% at the end of the fourth growth. Then, before the next growth, the compensation source furnaces Ga2, Al2 and In2 are cooled down to return their beam currents to the beam current values ​​f1(Ga), f1(Al) and f1(In) before the first growth. At the same time, the growth source furnaces Ga2, Al2 and In2 are heated up to T2(Ga), T2(Al) and T2(In). The beam currents are returned to the beam current values ​​F1(Ga), F1(Al) and F1(In) before the first growth. Then the next growth is carried out.

[0050] The invention concept is described in detail using specific examples herein, and the description of the above embodiments is only used to help understand the core idea of ​​the invention. It should be pointed out that any obvious modification, equivalent substitution or other improvement made by a person of ordinary skill in the art without departing from the invention concept should be included in the protection scope of the present invention.

Claims

1. A molecular beam epitaxial growth control method, characterized in that: The molecular beam epitaxial growth material includes determining elements and excess elements, wherein the determining elements are elements whose beam flow directly affects the growth rate and / or composition, and the excess elements are elements whose growth rate and / or composition are not affected after the beam flow exceeds a certain value; A growth source furnace and a compensation source furnace are set for each determining element. The temperature of the growth source furnace is controlled according to an empirical curve and the temperature is kept stable during the growth process of each furnace. The temperature of the compensation source furnace is variable during the growth process of each furnace. The difference between the actual growth rate or beam current of the growth source furnace and the target growth rate or beam current is compensated by adjusting the temperature of the compensation source furnace. The growth rate or beam current provided by the growth source furnace accounts for 80% to 95% of the total rate or beam current; In the interval between two growths, the temperature of the growth source furnace and the compensation source furnace is adjusted by the following (1) or (2): (1) The temperature of the compensation source furnace drops to the state before the growth begins, and the temperature of the growth source furnace is raised; (2) Maintain the temperature of the growth source furnace and the compensation source furnace at the end of the previous growth, and directly proceed to the next growth; When it is estimated that at the end of the next growth, the percentage of the growth rate or beam current provided by the compensation source furnace to the total growth rate or beam current exceeds the set value, method (1) is used to adjust the temperature of the growth source furnace and the compensation source furnace.

2. The control method according to claim 1, characterized in that: The set value is a value between 10% and 20%.

3. The control method according to claim 1 or 2, characterized in that: When the total growth rate or beam current is monitored to deviate from the preset value by 0.5%~1.0%, the compensation source furnace temperature adjustment is performed.

4. The control method according to claim 1 or 2, characterized in that: When the optical thickness deviation of the molecular beam epitaxial growth product is monitored to be above 0.5%, the compensation source furnace temperature adjustment is performed.

5. The control method according to claim 1 or 2, characterized in that: The temperature change rate of the compensation source furnace is 0.1℃ / min ~0.5℃ / min.

6. The control method according to claim 1 or 2, characterized in that: The molecular beam epitaxial growth material is GaAs, AlAs or AlGaAs; Ga is the determining element and As is the excess element in GaAs; Al is the determining element and As is the excess element in AlAs; Ga and Al are the determining elements and As is the excess element in AlGaAs.

7. The control method according to claim 1 or 2, characterized in that: The molecular beam epitaxial growth material is InGaAs or InAlAs; InGaAs contains In and Ga as determining elements and As as an excess element; InAlAs contains In and Al as determining elements and As as an excess element.

8. The control method according to claim 1 or 2, characterized in that: The molecular beam epitaxial growth material is InP or InGaP; InP is the determining element and P is an excess element; InGaP is In and Ga are the determining elements and P is an excess element.

9. The control method according to claim 1 or 2, characterized in that: The molecular beam epitaxial growth material is InSb, InGaSb or InAlSb; InSb has In as the determining element and Sb as the excess element; InGaSb has In and Ga as the determining elements and Sb as the excess element; and InAlSb has In and Al as the determining elements and Sb as the excess element.

Images