Molecular beam epitaxy InGaAsP calibration method

Abstract

The invention provides a molecular beam epitaxy InGaAsP calibration method, and relates to the technical field of semiconductor manufacturing. The method comprises the following steps of: growing an In < x > < 1 > Ga < 1-x > < 1 > Asy1 < P < 1-y > < 1 > epitaxial layer by adopting preset process parameters; performing X-ray diffraction spectrum and PL spectrum measurement on the epitaxial layer; simultaneously determining a component x1 and a component y1 in the epitaxial layer through calculation; adjusting the preset process parameters, and taking the adjusted parameters as optimized process parameters; growing an epitaxial layer by adopting optimized process parameters; and repeating the steps until the relative deviation between the component measurement result of the epitaxial layer and the preset component is smaller than a preset threshold value, and determining the calibration process parameters of the epitaxial layer based on the final process parameters. According to the method, the X-ray diffraction spectrum and the PL spectrum of the InGaAsP epitaxial layer are combined at the same time, quantitative adjustment and calibration of growth process parameters are achieved, the complicated calibration process of a conventional quaternary system material is avoided, and cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, and in particular to a molecular beam epitaxy InGaAsP calibration method. Background Art

[0002] For quaternary materials grown by molecular beam epitaxy, it is generally required to match the substrate lattice to avoid growth defects caused by lattice mismatch. x Ga 1-x As y P 1-y Quaternary materials have countless x, y combinations that meet the lattice matching requirements of the same substrate (such as InP substrate). x Ga 1-x As y P 1-y The calibration of quaternary epitaxial material parameters brings difficulties.

[0003] In the molecular beam epitaxial growth of In with a specified composition ratio x Ga 1-x As y P 1-y In order to obtain the corresponding growth conditions for quaternary materials, firstly, In is grown multiple times. x Ga 1-x As ternary material, to determine the growth conditions of In beam source and Ga beam source, and then under the determined growth conditions of In beam source and Ga beam source, gradually adjust the beam equivalent pressure of As or P to adjust the component ratio y, so as to finally obtain In x Ga 1-x As y P 1-y Growth conditions required for quaternary materials.

[0004] However, since the time and material cost of each epitaxial growth is high in the molecular beam epitaxy production process, if the In x Ga 1-x As y P 1-y The growth conditions required for quaternary materials, then for InGaAsP quaternary materials with different component ratios, a lot of time and materials are needed each time to determine the corresponding growth conditions, which greatly increases the cost of molecular beam epitaxy production. Summary of the invention

[0005] The object of the present invention is to provide a molecular beam epitaxy InGaAsP calibration method to solve the problem of determining the growth process parameters of InGaAsP quaternary system materials of specified components in view of the above-mentioned deficiencies in the prior art.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: The present invention provides a molecular beam epitaxy InGaAsP calibration method, which is used to calibrate InGaAsP with a preset composition. x0 Ga 1-x0 As y0 P 1-y0 The method comprises: Step a: using preset process parameters to grow In on an InP substrate x1 Ga 1-x1 As y1 P 1-y1 Epitaxial layer, process parameters include indium source furnace temperature, gallium source furnace temperature, As beam equivalent pressure, P beam equivalent pressure; Step b, performing X-ray diffraction spectrum measurement and PL spectrum measurement on the epitaxial layer to obtain the relative position relationship between the main peak of the substrate and the 0th order peak of the epitaxial layer in the X-ray diffraction spectrum and the peak wavelength corresponding to the epitaxial layer in the PL spectrum; Step c, determining the values ​​of both the component x1 and the component y1 in the epitaxial layer by calculation according to the relative position relationship and the peak wavelength; Step d, adjusting the preset process parameters according to the determined components x1 and y1, wherein the adjustment is used to make the expected composition of the epitaxial layer grown next time equal to the preset components x0 and y0; Step e, growing an InGaAsP epitaxial layer on an InP substrate using adjusted process parameters; Step f, repeating steps b to e until the relative deviation between the composition of the grown epitaxial layer and the preset composition x0 and y0 is less than a preset threshold, and determining the growth In based on the process parameters of the finally grown epitaxial layer. x0 Ga 1- x0 As y0 P 1-y0 Scaling process parameters for epitaxial layers.

[0007] Optionally, step c includes: determining initial values ​​of x1 and y1 through a relative position relationship, and then adjusting the values ​​of x1 and y1 according to the peak wavelength, so that the values ​​of x1 and y1 finally satisfy both the relative position relationship and the peak wavelength.

[0008] Optionally, step c specifically includes: Step c1, initialize the values ​​of x1 and y1, and x1 Ga 1-x1 As y1 P 1-y1The X-ray diffraction spectrum of the epitaxial layer is simulated and calculated, and one of x1 and y1 is adjusted so that the relative position relationship between the main peak of the substrate and the 0-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by the simulation calculation is consistent with the relative position relationship obtained by the measurement in step b, and the values ​​of x1 and y1 determined at this time are recorded as x 10 and 10 ; Step c2: the peak wavelength measured in step b is recorded as λ, where λ is in nm. g0 =1240 / λ to calculate the bandgap width E g0 , E g0 The unit is eV; Step c3, calculate the value of x1 and y1 to be x 10 and 10 The theoretical bandgap width E g1 , E g1 The unit is eV; Step c4: On the premise that the relative position relationship between the main peak of the substrate and the zero-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by simulation calculation is consistent with the relative position relationship obtained by measurement, 10 and 10 The value of is adjusted so that the corresponding E g1 Equal to E g0 So far, and the last obtained x 10 and 10 The value of In x1 Ga 1-x1 As y1 P 1-y1 The values ​​of both the component x1 and the component y1 in the epitaxial layer.

[0009] Optionally, step d specifically includes: For the component x1 determined in step c, the adjustment value of the indium source furnace temperature and / or the gallium source furnace temperature is determined according to the predetermined relationship between the source furnace temperature and the molecular beam source rate, so that the expected composition of In after adjustment is equal to the preset composition x0; For the component y1 determined in step c, the P beam equivalent pressure remains unchanged, and the adjusted As beam equivalent pressure is determined by the following formula: adjusted As beam equivalent pressure = (1-y1)×y0 / (y1×(1-y0))×As beam equivalent pressure before adjustment.

[0010] Optionally, the thickness of the epitaxial layer grown in step a and step e is the same, and the thickness ranges from 100 nm to 500 nm.

[0011] Optionally, the preset threshold is 1%.

[0012] Optionally, in step f, the growth In is determined based on the process parameters of the final grown epitaxial layer. x0 Ga 1- x0 As y0 P 1-y0 The calibration process parameters of the epitaxial layer include: The process parameters of the final grown epitaxial layer are used as the growth parameters of In x0 Ga 1-x0 As y0 P 1-y0 Scaling process parameters for epitaxial layers; or The process parameter adjustment method in step d is used to adjust the process parameters of the epitaxial layer finally grown, and the adjusted process parameters are used as the process parameters for growing In x0 Ga 1-x0 As y0 P 1-y0 Scaling process parameters for epitaxial layers.

[0013] The beneficial effects of the present invention include: The molecular beam epitaxy InGaAsP calibration method provided by the present invention comprises: step a, using preset process parameters to grow In on an InP substrate x1 Ga 1-x1 As y1 P 1-y1 epitaxial layer, the process parameters include indium source furnace temperature, gallium source furnace temperature, As beam equivalent pressure, P beam equivalent pressure; step b, performing X-ray diffraction spectrum measurement and PL spectrum measurement on the epitaxial layer to obtain the relative position relationship between the main peak of the substrate and the 0-order peak of the epitaxial layer in the X-ray diffraction spectrum and the peak wavelength corresponding to the epitaxial layer in the PL spectrum; step c, according to the relative position relationship and the peak wavelength, by calculation, simultaneously determine the values ​​of both the component x1 and the component y1 in the epitaxial layer; step d, according to the determined component x1 and component y1, adjust the preset process parameters, the adjustment is used to make the expected component of the epitaxial layer grown next time equal to the preset components x0 and y0; step e, using the adjusted process parameters, grow an InGaAsP epitaxial layer on an InP substrate; step f, repeating steps b to e until the relative deviation between the component of the grown epitaxial layer and the preset components x0 and y0 is less than a preset threshold, and determining the growth In based on the process parameters of the epitaxial layer finally grown x0 Ga 1-x0 As y0 P 1-y0 Calibration process parameters of epitaxial layer. This method realizes quantitative adjustment and calibration of growth process parameters by combining both X-ray diffraction spectrum and PL spectrum of InGaAsP epitaxial layer, avoiding the complicated calibration process of conventional quaternary materials and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 The flowchart of the molecular beam epitaxy InGaAsP calibration method provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Since the time and material cost of each epitaxial growth in the molecular beam epitaxy production process is high, if the conventional calibration In x Ga 1-x As material, recalibrate In x Ga 1-x As y P 1-y The method of using quaternary materials will greatly increase the cost of molecular beam epitaxy production. Therefore, it is necessary to provide a calibration method for molecular beam epitaxy InGaAsP materials.

[0018] Figure 1 The flowchart of the molecular beam epitaxy InGaAsP calibration method provided by an embodiment of the present invention is shown.

[0019] The molecular beam epitaxy InGaAsP calibration method provided by the present invention is used to calibrate InGaAsP with a preset composition. x0 Ga 1-x0 As y0 P 1-y0 The growth process parameters of the quaternary material are calibrated, x0 represents the In component in the group III elements, and y0 represents the As component in the group V elements.

[0020] like Figure 1 As shown, the method includes: This method is used to calculate the In x0 Ga 1-x0 As y0 P 1-y0The method comprises: Step a: using preset process parameters to grow In on an InP substrate x1 Ga 1-x1 As y1 P 1-y1 For the epitaxial layer, the process parameters include the temperature of the indium source furnace, the temperature of the gallium source furnace, the equivalent pressure of the As beam, and the equivalent pressure of the P beam.

[0021] It should be noted that the growth temperature during epitaxial growth in this application is the same preset growth temperature. The components x1 and y1 here are determined by preset process parameters. Different process parameters correspond to different component values. The preset process parameters here are the initial values ​​of the process parameters set based on previous experience.

[0022] Step b, measuring the X-ray diffraction spectrum and the PL spectrum of the epitaxial layer to obtain the relative position relationship between the main peak of the substrate and the zero-order peak of the epitaxial layer in the X-ray diffraction spectrum and the peak wavelength corresponding to the epitaxial layer in the PL spectrum. The PL spectrum here can be, for example, a room temperature PL spectrum.

[0023] Step c: According to the relative position relationship and the peak wavelength, the values ​​of the components x1 and y1 in the epitaxial layer are simultaneously determined by calculation.

[0024] Optionally, step c includes: determining initial values ​​of x1 and y1 through a relative position relationship, and then adjusting the values ​​of x1 and y1 according to the peak wavelength, so that the values ​​of x1 and y1 finally satisfy both the relative position relationship and the peak wavelength.

[0025] Optionally, step c specifically includes: Step c1, initialize the values ​​of x1 and y1, and x1 Ga 1-x1 As y1 P 1-y1 The X-ray diffraction spectrum of the epitaxial layer is simulated and calculated, and one of x1 and y1 is adjusted so that the relative position relationship between the main peak of the substrate and the 0-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by the simulation calculation is consistent with the relative position relationship obtained by the measurement in step b, and the values ​​of x1 and y1 determined at this time are recorded as x 10 and 10 .

[0026] Step c2: the peak wavelength measured in step b is recorded as λ, where λ is in nm. g0 =1240 / λ to calculate the bandgap width E g0 , E g0 The unit is eV.

[0027] Step c3, calculate the value of x1 and y1 to be x 10 and 10 The theoretical bandgap width E g1 , E g1 The unit is eV.

[0028] For example, E can be calculated according to the following formula g1 : .

[0029] Step c4: On the premise that the relative position relationship between the main peak of the substrate and the zero-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by simulation calculation is consistent with the relative position relationship obtained by measurement, 10 and 10 The value of is adjusted so that the corresponding E g1 Equal to E g0 So far, and the last obtained x 10 and 10 The value of In x1 Ga 1-x1 As y1 P 1-y1 The values ​​of both the component x1 and the component y1 in the epitaxial layer.

[0030] Specifically, in step c4, E g1 With E g0 For comparison, if E g1 = E g0 , then x at this time 10 and 10 As In x1 Ga 1-x1 As y1 P 1-y1 The specific values ​​of the components x1 and y1 in the epitaxial layer; if E g1 <E g0 , increase x by a preset step size 10 At the same time, in order to keep the relative position relationship between the main peak of the substrate and the 0-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by simulation calculation in step c1 consistent with the relative position relationship obtained by measurement in step b, the corresponding reduction of y 10 The value of x is then used to update 10 and 10 , according to E in step c3 g1 Calculate the formula to recalculate E g1 Then, E g1 With E g0 For comparison, gradually increase x 10 The value of and correspondingly reduce y 10 until the calculated Eg1 Equal to E g0 So far, and the last obtained x 10 and 10 The value of In x1 Ga 1-x1 As y1 P 1-y1 The specific values ​​of the components x1 and y1 in the epitaxial layer. If E g1 >E g0 , decrease x by a preset step size 10 At the same time, in order to keep the relative position relationship between the main peak of the substrate and the 0-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by simulation calculation in step c1 consistent with the relative position relationship obtained by measurement in step b, the corresponding increase of y 10 The value of x is then used to update 10 and 10 , according to E in step c3 g1 Calculate the formula to recalculate E g1 Then, E g1 With E g0 Compare and gradually reduce x 10 The value of and correspondingly increase y 10 until the calculated E g1 Equal to E g0 So far, and the last obtained x 10 and 10 The value of In x1 Ga 1-x1 As y1 P 1-y1 The specific values ​​of the components x1 and y1 in the epitaxial layer are in the range of a preset step size greater than or equal to 0.001 and less than or equal to 0.01.

[0031] Step d: adjusting the preset process parameters according to the determined components x1 and y1, wherein the adjustment is used to make the expected composition of the epitaxial layer grown next time equal to the preset components x0 and y0.

[0032] Optionally, step d specifically includes: for the component x1 determined in step c, the adjustment value of the indium source furnace temperature and / or the gallium source furnace temperature is determined according to the pre-determined relationship between the source furnace temperature and the molecular beam source rate, so that the expected component of In after adjustment is equal to the preset component x0. Specifically, for the component x1 determined in step c, if x1 = x0, the temperatures of both the indium source furnace and the gallium source furnace remain unchanged; if x1 > x0, the temperature of the indium source furnace is decreased, or the temperature of the gallium source furnace is increased, or both the temperature of the indium source furnace is decreased and the temperature of the gallium source furnace is increased; if x1 < x0, the temperature of the indium source furnace is increased, or the temperature of the gallium source furnace is decreased, or both the temperature of the indium source furnace is increased and the temperature of the gallium source furnace is decreased; the adjustment value of the indium source furnace temperature and / or the gallium source furnace temperature is determined according to the pre-determined relationship between the source furnace temperature and the molecular beam source rate, so that the expected component of In in the group III elements after adjustment is equal to the preset component x0. For the component y1 determined in step c, the equivalent pressure of the P beam remains unchanged, and the adjusted equivalent pressure of the As beam is calculated according to the following formula: Adjusted equivalent pressure of As beam = (1 - y1) × y0 / (y1 × (1 - y0)) × Adjusted equivalent pressure of As beam before adjustment.

[0033] Step e: Using the adjusted process parameters, grow an InGaAsP epitaxial layer on an InP substrate.

[0034] Step f: Repeat steps b to e until the relative deviations of the components of the grown epitaxial layer from the preset components x0 and y0 are less than a preset threshold, and determine the calibration process parameters for growing the In x0 Ga 1- x0 As y0 P 1-y0 epitaxial layer based on the process parameters of the finally grown epitaxial layer. Specifically, repeat steps b to e until the relative deviations of the In component and the As component of the grown epitaxial layer from the corresponding preset components x0 and y0 are both less than the preset threshold, and determine the calibration process parameters for growing the In x0 Ga 1-x0 As y0 P 1-y0 epitaxial layer. Optionally, the preset threshold is 1%.

[0035] Optionally, the thicknesses of the epitaxial layers grown in steps a and e are the same, and the range of the thickness is as follows: 100 nm to 500 nm.

[0036] Optionally, in step f, determine the calibration process parameters for growing the In x0 Ga 1- x0 As y0 P1-y0 The calibration process parameters of the epitaxial layer specifically include: using the process parameters of the final grown epitaxial layer as the growth In x0 Ga 1-x0 As y0 P 1-y0 or using the process parameter adjustment method in step d to adjust the process parameters of the final grown epitaxial layer, and using the adjusted process parameters as the growth In x0 Ga 1-x0 As y0 P 1-y0 Scaling process parameters for epitaxial layers.

[0037] In actual operation, according to the method of the present application, it is usually only necessary to grow the InGaAsP epitaxial layer 1 to 2 times (maximum 3 times) to obtain the desired calibration process parameters. The present method achieves quantitative adjustment and calibration of the growth process parameters by combining both the X-ray diffraction spectrum and the PL spectrum of the InGaAsP epitaxial layer, avoiding the complicated calibration process of conventional quaternary materials and saving costs.

[0038] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A molecular beam epitaxy InGaAsP calibration method, characterized in that: The method is used to determine the In x0 Ga 1-x0 As y0 P 1-y0 The growth process parameters are calibrated, and the method comprises: Step a: using preset process parameters to grow In on an InP substrate x1 Ga 1-x1 As y1 P 1-y1 Epitaxial layer, process parameters include indium source furnace temperature, gallium source furnace temperature, As beam equivalent pressure, P beam equivalent pressure; Step b, performing X-ray diffraction spectrum measurement and PL spectrum measurement on the epitaxial layer to obtain the relative position relationship between the main peak of the substrate and the 0th order peak of the epitaxial layer in the X-ray diffraction spectrum and the peak wavelength corresponding to the epitaxial layer in the PL spectrum; Step c, determining the values ​​of both the component x1 and the component y1 in the epitaxial layer by calculation according to the relative position relationship and the peak wavelength; Step d, adjusting the preset process parameters according to the determined components x1 and y1, wherein the adjustment is used to make the expected composition of the epitaxial layer grown next time equal to the preset components x0 and y0; Step e, growing an InGaAsP epitaxial layer on an InP substrate using adjusted process parameters; Step f, repeating steps b to e until the relative deviation between the composition of the grown epitaxial layer and the preset composition x0 and y0 is less than a preset threshold, and determining the growth In based on the process parameters of the finally grown epitaxial layer. x0 Ga 1- x0 As y0 P 1-y0 Scaling process parameters for epitaxial layers.

2. The molecular beam epitaxy InGaAsP calibration method according to claim 1, characterized in that: The step c comprises: determining the initial values ​​of x1 and y1 through the relative position relationship, and then adjusting the values ​​of x1 and y1 according to the peak wavelength, so that the values ​​of x1 and y1 finally satisfy both the relative position relationship and the peak wavelength.

3. The molecular beam epitaxy InGaAsP calibration method according to claim 2, characterized in that: The step c specifically comprises: Step c1, initialize the values ​​of x1 and y1, and x1 Ga 1-x1 As y1 P 1-y1 The X-ray diffraction spectrum of the epitaxial layer is simulated and calculated, and one of x1 and y1 is adjusted so that the relative position relationship between the main peak of the substrate and the 0-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by the simulation calculation is consistent with the relative position relationship obtained by the measurement in step b, and the values ​​of x1 and y1 determined at this time are recorded as x 10 and 10 ; Step c2: the peak wavelength measured in step b is recorded as λ, where λ is in nm. g0 =1240 / λ to calculate the bandgap width E g0 , E g0 The unit is eV; Step c3, calculate the value of x1 and y1 to be x 10 and 10 The theoretical bandgap width E g1 , E g1 The unit is eV; Step c4: On the premise that the relative position relationship between the main peak of the substrate and the zero-order peak of the epitaxial layer in the X-ray diffraction spectrum obtained by simulation calculation is consistent with the relative position relationship obtained by measurement, 10 and 10 The value of is adjusted so that the corresponding E g1 Equal to E g0 So far, and the last obtained x 10 and 10 The value of In x1 Ga 1-x1 As y1 P 1-y1 The values ​​of both the component x1 and the component y1 in the epitaxial layer.

4. The molecular beam epitaxy InGaAsP calibration method according to claim 1, characterized in that: The step d specifically comprises: For the component x1 determined in step c, the adjustment value of the indium source furnace temperature and / or the gallium source furnace temperature is determined according to the predetermined relationship between the source furnace temperature and the molecular beam source rate, so that the expected composition of In after adjustment is equal to the preset composition x0; For the component y1 determined in step c, the P beam equivalent pressure remains unchanged, and the adjusted As beam equivalent pressure is determined by the following formula: adjusted As beam equivalent pressure = (1-y1)×y0 / (y1×(1-y0))×As beam equivalent pressure before adjustment.

5. The molecular beam epitaxy InGaAsP calibration method according to any one of claims 1 to 4, characterized in that: The thickness of the epitaxial layer grown in step a and step e is the same, and the thickness ranges from 100 nm to 500 nm.

6. The molecular beam epitaxy InGaAsP calibration method according to any one of claims 1 to 4, characterized in that: The preset threshold is 1%.

7. The molecular beam epitaxy InGaAsP calibration method according to claim 6, characterized in that: In step f, the growth In is determined based on the process parameters of the final grown epitaxial layer. x0 Ga 1-x0 As y0 P 1-y0 The calibration process parameters of the epitaxial layer include: The process parameters of the final grown epitaxial layer are used as the growth parameters of In x0 Ga 1-x0 As y0 P 1-y0 Scaling process parameters for epitaxial layers; or The process parameter adjustment method in step d is used to adjust the process parameters of the epitaxial layer finally grown, and the adjusted process parameters are used as the process parameters for growing In x0 Ga 1-x0 As y0 P 1-y0 Scaling process parameters for epitaxial layers.

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