Strained compensation growth method of indium arsenide / aluminum antimonide superlattice and superlattice structure

Abstract

The application relates to the technical field of semiconductor devices, and particularly provides an indium arsenide / aluminum antimonide superlattice strain compensation growth method and a superlattice structure. 1‑ x Sb x The strain compensation layer, the third thickness of the aluminum antimonide barrier layer, the InAs 1‑x Sb x The strain compensation layer, and a period unit is obtained, wherein the antimony component x satisfies 0.1<=x<=0.4, the second thickness is greater than or equal to 0.2 nm and less than or equal to 2 nm, the first thickness, the antimony component x, the second thickness and the third thickness satisfy a balance condition, the balance condition is that the total amount of tensile strain in the period unit is equal to the total amount of compressive strain; a preset number of period units are sequentially grown on the period unit to obtain the indium arsenide / aluminum antimonide superlattice. The problem that it is difficult to guarantee the device performance after the indium arsenide / aluminum antimonide superlattice is subjected to strain compensation in the related art is solved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to an indium arsenide / aluminum antimonide superlattice strain-compensated growth method and superlattice structure. Background Technology

[0002] InAs (indium arsenide) / AlSb (aluminum antimonide) superlattices, as an important branch of type-two superlattice materials, possess unique band structures and carrier transport properties, showing broad application prospects in mid- and long-wave infrared detection and high-frequency laser devices. However, InAs / AlSb superlattices cannot achieve natural lattice matching with the substrate. The alternating growth of InAs and AlSb layers leads to stress accumulation, causing material warping and increased defect density, severely affecting device performance.

[0003] Specifically, the lattice constant of InAs is 0.6058 nm, that of AlSb is 0.6135 nm, and that of GaSb (gallium antimonide) is 0.6095 nm. When growing an InAs / AlSb superlattice on a GaSb substrate, InAs induces a tensile strain of 0.617%, and AlSb induces a compressive strain of 0.649%. Since there are no shared atoms between InAs and AlSb, only Al-As or In-Sb bonds can exist at their interfaces, forming an AlAs interface material layer or an InSb-like interface material layer. The AlAs interface material layer forms a 6.7% tensile strain with the InAs substrate, the InSb-like interface material layer forms a 6.9% compressive strain with the InAs substrate, the AlAs interface material layer forms a 7.3% tensile strain with the GaSb substrate, and the InSb-like interface material layer forms a 6.3% compressive strain with the GaSb substrate. In other words, when growing InAs / AlSb superlattices on GaSb or InAs substrates, a significant lattice mismatch exists between the InAs and AlSb materials, preventing the InAs / AlSb superlattice from achieving a natural lattice match with the substrate. To address this, molecular beam epitaxy (MBE) methods require strain compensation techniques to balance the lattice mismatch, such as adjusting the monolayer thickness ratio. However, this method offers limited design freedom, resulting in suboptimal crystal quality of the fabricated superlattice material and sacrificing some device performance.

[0004] There is currently no effective solution to the problem of ensuring device performance after strain compensation of indium arsenide / aluminum antimonide superlattices in related technologies. Summary of the Invention

[0005] The present invention provides an indium arsenide / aluminum antimonide superlattice strain-compensated growth method and superlattice structure, which at least solves the problem in related technologies that it is difficult to guarantee device performance after strain compensation of indium arsenide / aluminum antimonide superlattices.

[0006] This invention provides a strain-compensated growth method for indium arsenide / aluminum antimonide superlattice, comprising: growing an indium arsenide layer of a first thickness on a target substrate; and growing an InAs layer of a second thickness on the indium arsenide layer. 1-x Sb x Strain compensation layer, wherein InAs 1-x Sb x The antimony composition x of the strain compensation layer satisfies 0.1 ≤ x ≤ 0.4, and the second thickness is greater than or equal to 0.2 nm and less than or equal to 2 nm; in InAs 1-x Sb x A third-thickness aluminum antimonide barrier layer is grown on the strain compensation layer; an InAs layer is grown on the aluminum antimonide barrier layer. 1-x Sb x A strain compensation layer is used to obtain periodic units, wherein the periodic units are composed of indium arsenide layers and InAs layers connected in sequence. 1-x Sb x Strain compensation layer, aluminum antimonide barrier layer and InAs 1-x Sb x The superlattice structure composed of strain compensation layers satisfies the equilibrium condition of the first thickness, antimony composition x, second thickness, and third thickness. The equilibrium condition is that the total tensile strain in the periodic unit is equal to the total compressive strain. A predetermined number of periodic units are grown sequentially on the periodic unit to obtain an indium arsenide / aluminum antimonide superlattice.

[0007] In one embodiment of the present invention, growing an indium arsenide layer of a first thickness on a target substrate includes: sequentially performing degassing and deoxidation treatments on the target substrate to obtain a pretreated substrate; growing a buffer layer on the pretreated substrate; and growing an indium arsenide layer of a first thickness on the buffer layer.

[0008] In one embodiment of the present invention, the target substrate is a gallium antimonide substrate, and the buffer layer is a gallium antimonide buffer layer; the target substrate is subjected to degassing and deoxidation treatments in sequence to obtain a pretreated substrate, including: placing the gallium antimonide substrate into the pretreatment chamber of a molecular beam epitaxy (MBE) apparatus, and performing degassing treatment on the gallium antimonide substrate in a vacuum environment and at a first heating temperature to obtain a substrate to be deoxidized; placing the substrate to be deoxidized into the growth chamber of the MBE apparatus, and performing deoxidation treatment on the substrate to be deoxidized in an antimony atmosphere protection environment and at a second heating temperature to obtain a pretreated substrate, wherein the second heating temperature is greater than the first heating temperature.

[0009] In one embodiment of the present invention, the second heating temperature is 570±1℃; a gallium antimonide buffer layer is grown on the pretreatment substrate at a growth temperature of 540~550℃, wherein the thickness of the gallium antimonide buffer layer is 100~300nm; before growing an indium arsenide layer of a first thickness on the buffer layer, the method further includes: adjusting the temperature of the pretreatment substrate on which the buffer layer is grown to 455~475℃.

[0010] In one embodiment of the present invention, a second InAs layer of a certain thickness is grown on the indium arsenide layer. 1-x Sb x Before the strain compensation layer, the above method further includes: shutting down the indium beam source control unit of the molecular beam epitaxy equipment, interrupting growth during a first interruption time and keeping the antimony beam source control unit of the molecular beam epitaxy equipment open to allow the antimony beam to surface wet the indium arsenide layer; in InAs 1-x Sb x Before growing a third-thickness aluminum antimonide barrier layer on the strain compensation layer, the method further includes: shutting down the indium beam source control component and the arsenic beam source control component of the molecular beam epitaxy equipment, interrupting growth during a second interruption time while keeping the antimony beam source control component open, so that the antimony beam current can be directed to the InAs grown on the indium arsenide layer. 1-x Sb x The strain compensation layer is surface-wetted; an InAs layer is grown on the aluminum antimonide barrier layer. 1-x Sb x Prior to the strain compensation layer, the method further includes: shutting down the aluminum beam current source control component of the molecular beam epitaxy equipment, interrupting growth during a third interruption time while keeping the antimony beam current source control component open to allow the antimony beam to surface-wet the aluminum antimonide barrier layer; and growing an InAs layer on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic cells in the strain compensation layer, the method further includes: shutting off the indium beam source control component and the arsenic beam source control component, interrupting the growth during the fourth interruption time while keeping the antimony beam source control component on, so that the antimony beam current can affect the InAs grown on the aluminum antimonide barrier layer. 1-x Sb x The strain compensation layer is surface-wetted; wherein the first interruption time, the second interruption time, the third interruption time and the fourth interruption time are all greater than or equal to 1 second and less than or equal to 10 seconds.

[0011] In one embodiment of the present invention, an InAs layer is grown on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic element through the strain compensation layer, the method further includes: performing X-ray diffraction scanning on the periodic element to obtain a first scanning result; and adjusting the InAs if the first scanning result does not meet a first preset condition. 1-xSb x The antimony composition x and the second thickness of the strain compensation layer are used to grow new periodic units on the target substrate.

[0012] In one embodiment of the present invention, an InAs layer is grown on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic unit through the strain compensation layer, the above method further includes: scanning the periodic unit using an atomic force microscope to obtain a second scanning result; and adjusting the InAs if the first scanning result does not meet the first preset condition, and / or the second scanning result does not meet the second preset condition. 1-x Sb x The antimony composition x and the second thickness of the strain compensation layer are used to grow new periodic units on the target substrate.

[0013] In one embodiment of the present invention, the first preset condition is that the zero-order satellite peak of the periodic unit coincides with the characteristic diffraction peak of the target substrate, and the second preset condition is that the periodic unit is in The surface roughness within the scanning range is less than 0.8 nm.

[0014] In one embodiment of the present invention, the preset number is 49 and the total number of periodic units is 50; after the preset number of periodic units are grown sequentially on the periodic units to obtain the indium arsenide / aluminum antimonide superlattice, the above method further includes: adjusting the temperature of the indium arsenide / aluminum antimonide superlattice to less than 250°C under an antimony atmosphere protection environment before taking it out.

[0015] This invention also provides an indium arsenide / aluminum antimonide superlattice structure, comprising an indium arsenide layer and a first InAs layer. 1-x Sb x Strain compensation layer, aluminum antimonide barrier layer, second InAs 1-x Sb x Strain compensation layer; Indium arsenide layer, first InAs 1- x Sb x Strain compensation layer, aluminum antimonide barrier layer, and second InAs 1-x Sb x The strain compensation layers are connected sequentially along the preset growth direction; the first InAs 1-x Sb x Strain compensation layer and second InAs 1-x Sb x The strain compensation layer is the same; the first InAs 1-x Sb x The antimony composition x of the strain compensation layer satisfies 0.1 ≤ x ≤ 0.4, and the first InAs 1-x Sb xThe second thickness of the strain compensation layer is greater than or equal to 0.2 nm and less than or equal to 2 nm; the antimony composition x, the second thickness, the first thickness of the indium arsenide layer, and the third thickness of the aluminum antimonide barrier layer satisfy the equilibrium condition, which is that the total tensile strain in the indium arsenide / aluminum antimonide superlattice structure is equal to the total compressive strain.

[0016] This invention provides a strain-compensated growth method and superlattice structure for indium arsenide / aluminum antimonide superlattice, introducing InAs with an adjustable lattice constant. 1-x Sb x Strain compensation layer, where the antimony composition x satisfies 0.1 ≤ x ≤ 0.4, InAs 1-x Sb x When the second thickness of the strain compensation layer is greater than or equal to 0.2 nm and less than or equal to 2 nm, the compressive strain of the indium arsenide (InAsSb) material can be used to offset the net tensile strain caused by the accumulation of lattice mismatch at the indium arsenide / aluminum antimonide interface, achieving local stress balance within a periodic unit. This results in a high crystal quality in the obtained indium arsenide / aluminum antimonide superlattice, leading to superior performance in semiconductor devices fabricated based on this superlattice. This solves the problem in related technologies where it is difficult to guarantee device performance after strain compensation of the indium arsenide / aluminum antimonide superlattice. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other embodiments based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the steps of an indium arsenide / aluminum antimonide superlattice strain-compensated growth method in an embodiment of the present invention.

[0019] Figure 2 This is an X-ray diffraction scan result of the indium arsenide / aluminum antimonide superlattice sample in an embodiment of the present invention.

[0020] Figure 3 This is an atomic force microscopy scan of the indium arsenide / aluminum antimonide superlattice sample in an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of an indium arsenide / aluminum antimonide superlattice structure in an embodiment of the present invention.

[0022] The above figures include the following reference numerals:

[0023] 41. Indium arsenide layer; 42. First InAs 1-x Sb x 43. Strain compensation layer; 44. Aluminum antimonide barrier layer; 45. Second InAs 1- x Sb x Strain compensation layer; A. Preset growth direction. Detailed Implementation

[0024] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0025] The lattice constant of indium arsenide is 0.6058 nm, while that of aluminum antimonide is 0.6135 nm. Taking gallium antimonide substrate as an example, the lattice constant of gallium antimonide is 0.6095 nm. When growing an indium arsenide / aluminum antimonide superlattice on a gallium antimonide substrate, indium arsenide induces a tensile strain of 0.617%, while aluminum antimonide induces a compressive strain of 0.649%. Since there are no shared atoms between indium arsenide and aluminum antimonide, only aluminum-arsenic (Al-As) bonds or indium-antimonide (In-Sb) bonds can exist at their interface, forming an aluminum arsenide interface material layer or an indium antimonide-like interface material layer. A 6.7% tensile strain is formed between the aluminum arsenide interface material layer and the indium arsenide substrate, a 6.9% compressive strain is formed between the indium antimonide-like interface material layer and the indium arsenide substrate, a 7.3% tensile strain is formed between the aluminum arsenide interface material layer and the gallium antimonide substrate, and a 6.3% compressive strain is formed between the indium antimonide-like interface material layer and the gallium antimonide substrate. In other words, when growing indium arsenide / aluminum antimonide superlattices on gallium antimonide or indium arsenide substrates, there is a significant lattice mismatch between the indium arsenide and aluminum antimonide materials, preventing the indium arsenide / aluminum antimonide superlattice from achieving natural lattice matching with the substrate.

[0026] In the related molecular beam epitaxy (MBE) growth method, strain compensation techniques are needed to balance lattice mismatch, such as adjusting the monolayer thickness ratio. However, this method has limited design freedom, and the crystal quality of the superlattice material produced is not good enough, which will sacrifice some device performance.

[0027] Therefore, please refer to Figure 1 As shown, this invention provides a strain-compensated growth method for indium arsenide / aluminum antimonide superlattices, including steps S101 to S105. This method ensures device performance after strain compensation of the indium arsenide / aluminum antimonide superlattice.

[0028] Step S101: Grow an indium arsenide layer of first thickness on the target substrate.

[0029] Step S102: A second InAs layer of a second thickness is grown on the indium arsenide layer. 1-x Sb x Strain compensation layer, wherein InAs 1-x Sb x The antimony composition x of the strain compensation layer satisfies 0.1≤x≤0.4, and the second thickness is greater than or equal to 0.2nm and less than or equal to 2nm.

[0030] Step S103, in InAs 1-x Sb x A third-thickness aluminum antimonide barrier layer is grown on the strain compensation layer.

[0031] Step S104: Grow an InAs layer on the aluminum antimonide barrier layer. 1-x Sb x A strain compensation layer is used to obtain periodic units, wherein the periodic units are composed of indium arsenide layers and InAs layers connected in sequence. 1-x Sb x Strain compensation layer, aluminum antimonide barrier layer and InAs 1-x Sb x The superlattice structure composed of strain compensation layers satisfies the equilibrium condition for the first thickness, antimony composition x, second thickness, and third thickness. The equilibrium condition is that the total tensile strain within the periodic unit is equal to the total compressive strain.

[0032] Step S105: A predetermined number of periodic cells are grown sequentially on the periodic cells to obtain an indium arsenide / aluminum antimonide superlattice.

[0033] The target substrate can be, but is not limited to, gallium antimonide (GaSb) substrates, indium antimonide (InSb) substrates, aluminum antimonide (AlSb) substrates, and indium arsenide (InAs) substrates. The embodiments of this invention will be described in detail below using a gallium antimonide substrate as an example.

[0034] In the embodiments of this invention, the indium arsenide antimony (InAsSb) layer and InAs 1-x Sb x The strain compensation layer describes the same object. By introducing an indium arsenide antimony layer with an adjustable lattice constant as a strain compensation layer, which acts like a shim, the average lattice constant of the entire superlattice period can be flexibly adjusted to precisely match the target substrate, thereby suppressing dislocation generation and increase at the source. Specifically, the lattice constant of the ternary alloy indium arsenide antimony material can be adjusted by varying the amount of antimony in the lattice. ~ 6.058Å and a ~The strain can be continuously adjusted between 6.479 Å, making it easy to achieve precise strain control.

[0035] InAs in step S102 1-x Sb x Strain compensation layer, InAs in step S104 1-x Sb x The strain compensation layer is identical in composition and thickness.

[0036] If the antimony component x is less than 0.1, it will lead to InAs 1-x Sb x The compressive strain of the strain compensation layer is insufficient. If the antimony composition x is higher than 0.4, it will introduce new lattice mismatch or phase separation problems.

[0037] InAs 1-x Sb x The second thickness of the strain compensation layer is controlled within an ultrathin range of 0.2-2 nm, which facilitates the determination of the first thickness of the indium arsenide layer and the third thickness of the aluminum antimonide barrier layer based on equilibrium conditions and the antimony composition x. Specifically, after selecting specific values ​​for the antimony composition x and the second thickness, those skilled in the art can determine the specific values ​​of the first and second thicknesses based on equilibrium conditions through a limited number of experiments; alternatively, they can query a database to determine the first and second thicknesses corresponding to the specific values ​​of the antimony composition x and the second thickness. This database is pre-established through a limited number of experiments combined with mathematical calculations.

[0038] In summary, when the antimony composition x satisfies 0.1 ≤ x ≤ 0.4 and the second thickness is greater than or equal to 0.2 nm and less than or equal to 2 nm, a strain layer can be inserted inside the superlattice period, specifically, InAs inserted between the indium arsenide layer and the aluminum antimonide barrier layer. 1- x Sb x Instead of using the indium arsenide-antimony layer as an external buffer layer, the strain compensation layer can use the compressive strain of the indium arsenide-antimony material to offset the net tensile strain caused by the accumulation of lattice mismatch at the indium arsenide / aluminum antimony interface, thus achieving local stress balance within a periodic unit. This is the key to achieving in-situ and efficient compensation.

[0039] The indium arsenide / aluminum antimonide superlattice prepared by this method has high crystal quality, and experimental images will be provided later in this embodiment to verify and illustrate this.

[0040] Meanwhile, by adjusting the two parameters of antimony composition x and second thickness, the strain compensation amount and band structure can be controlled independently, providing greater freedom for device design in different target bands, and the process has good repeatability, making it suitable for mass production.

[0041] Additionally, the InAs layer grown in step 1041-x Sb x The strain compensation layer can be understood as being inserted between the aluminum antimonide barrier layer of the current periodic unit and the indium arsenide layer of the next periodic unit, and is also used for strain compensation.

[0042] The growth method provided in the embodiments of the present invention can be achieved at least by molecular beam epitaxy (MBE) technology, specifically by growing with a molecular beam epitaxy device, to achieve atomic-level precision control of layer thickness and composition.

[0043] In one embodiment of the present invention, step S101, growing an indium arsenide layer of a first thickness on a target substrate, includes: sequentially performing degassing and deoxidation treatments on the target substrate to obtain a pretreated substrate; growing a buffer layer on the pretreated substrate; and growing an indium arsenide layer of a first thickness on the buffer layer.

[0044] Deoxidation treatment helps to obtain a clean, ordered target substrate surface.

[0045] In one embodiment of the present invention, the target substrate is a gallium antimonide substrate, and the buffer layer is a gallium antimonide buffer layer.

[0046] The target substrate is subjected to degassing and deoxidation treatments sequentially to obtain a pretreated substrate, including: placing a gallium antimonide substrate into the pretreatment chamber of a molecular beam epitaxy (MBE) apparatus, and degassing the gallium antimonide substrate in a vacuum environment and at a first heating temperature to obtain a substrate to be deoxidized; placing the substrate to be deoxidized into the growth chamber of the MBE apparatus, and deoxidizing the substrate to be deoxidized in an antimony atmosphere and at a second heating temperature to obtain a pretreated substrate, wherein the second heating temperature is higher than the first heating temperature.

[0047] In one embodiment of the present invention, the second heating temperature is 570±1℃.

[0048] A gallium antimonide buffer layer is grown on a pretreated substrate at a growth temperature of 540~550℃, wherein the thickness of the gallium antimonide buffer layer is 100~300nm.

[0049] Before growing an indium arsenide layer of the first thickness on the buffer layer, the method further includes adjusting the temperature of the pretreated substrate with the buffer layer to 455~475℃. This helps to ensure that atoms have sufficient mobility to fill deposition vacancies and form a long-range ordered lattice structure during the subsequent growth of the indium arsenide / aluminum antimonide superlattice, while avoiding excessive atomic diffusion that leads to interlayer mixing, thereby reducing lattice defects and dislocation density.

[0050] In one embodiment of this invention, in order to achieve interface smoothing and reduce the cross-mixing of arsenic and antimony atoms, a growth interruption method is used to grow the indium arsenide layer and InAs... 1-xSb x During the growth and switching process of the strain compensation layer, and in InAs 1-x Sb x Interface control is performed during the growth switching process between the strain compensation layer and the aluminum antimonide barrier layer, as shown below.

[0051] Step S102: A second InAs layer of a second thickness is grown on the indium arsenide layer. 1-x Sb x Before the strain compensation layer, the above method further includes: turning off the indium beam source control component of the molecular beam epitaxy equipment, interrupting growth during a first interruption time and keeping the antimony beam source control component of the molecular beam epitaxy equipment open, so that the antimony beam can surface-wet the indium arsenide layer.

[0052] Step S103, in InAs 1-x Sb x Before growing a third-thickness aluminum antimonide barrier layer on the strain compensation layer, the method further includes: shutting down the indium beam source control component and the arsenic beam source control component of the molecular beam epitaxy equipment, interrupting growth during a second interruption time while keeping the antimony beam source control component open, so that the antimony beam current can be directed to the InAs grown on the indium arsenide layer. 1- x Sb x The strain compensation layer is surface-impregnated.

[0053] Step S104: Grow an InAs layer on the aluminum antimonide barrier layer. 1-x Sb x Before the strain compensation layer, the above method further includes: shutting down the aluminum beam current source control component of the molecular beam epitaxy equipment, interrupting growth during the third interruption time and keeping the antimony beam current source control component open, so that the antimony beam current can surface-wet the aluminum antimonide barrier layer.

[0054] Step S104: Grow an InAs layer on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic cells in the strain compensation layer, the method further includes: shutting off the indium beam source control component and the arsenic beam source control component, interrupting the growth during the fourth interruption time while keeping the antimony beam source control component on, so that the antimony beam current can affect the InAs grown on the aluminum antimonide barrier layer. 1-x Sb x The strain compensation layer is surface-impregnated.

[0055] The first, second, third, and fourth interrupt times are all greater than or equal to 1 second and less than or equal to 10 seconds.

[0056] In one embodiment of the present invention, step S104 involves growing an InAs layer on the aluminum antimonide barrier layer. 1-x Sbx After obtaining the periodic element through the strain compensation layer, the method further includes: performing X-ray diffraction (XRD) scanning on the periodic element to obtain a first scanning result; and adjusting the InAs layer if the first scanning result does not meet a first preset condition. 1-x Sb x The antimony composition x and the second thickness of the strain compensation layer are used to grow new periodic units on the target substrate.

[0057] X-ray diffraction (XRD) can specifically be high-resolution X-ray diffraction (HRXRD).

[0058] In one embodiment of the present invention, step S104 involves growing an InAs layer on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic unit through the strain compensation layer, the above method further includes: scanning the periodic unit using an atomic force microscope (AFM) to obtain a second scanning result; and adjusting the InAs if the first scanning result does not meet a first preset condition, and / or the second scanning result does not meet a second preset condition. 1-x Sb x The antimony composition x and the second thickness of the strain compensation layer are used to grow new periodic units on the target substrate.

[0059] This helps ensure that the final indium arsenide / aluminum antimonide superlattice has high crystal quality, thereby enabling semiconductor devices based on this indium arsenide / aluminum antimonide superlattice, such as infrared detectors, to have excellent performance, including but not limited to exhibiting lower dark current, higher detectivity, and the ability to operate at higher temperatures compared to similar devices based on related superlattice strain-compensated growth methods, thus reducing the requirements for cryogenic cooling in detection devices or systems.

[0060] Preferably, the first preset condition is that the zero-order satellite peak of the periodic unit coincides with the characteristic diffraction peak of the target substrate, and the second preset condition is that the periodic unit in The surface roughness within the scanning range is less than 0.8 nm.

[0061] In the case of high-resolution X-ray diffraction (HRXRD), the first preset condition is that sharp and high-order satellite peaks can be observed in the high-resolution X-ray diffraction pattern, and the zero-order satellite peaks almost coincide with the characteristic diffraction peaks of the target substrate.

[0062] Preferably, the preset quantity is 49, and the total number of periodic units is 50.

[0063] After sequentially growing a predetermined number of periodic cells on the periodic cells to obtain an indium arsenide / aluminum antimonide superlattice, the method further includes: adjusting the temperature of the indium arsenide / aluminum antimonide superlattice to below 250°C under an antimony atmosphere protection environment before removing it. Specifically, the temperature of the indium arsenide / aluminum antimonide superlattice needs to be adjusted slowly, for example, by cooling at a rate of 5~20°C / min.

[0064] By way of example, based on the method provided in the embodiments of the present invention, strain-compensated indium arsenide / aluminum antimonide superlattice material for long-wave infrared detection is grown, and the specific growth process of the sample is as follows.

[0065] An n-type GaSb(100) substrate was placed in the molecular beam epitaxy (MBE) pretreatment chamber and degassed at 300°C for 0.5 hours. The substrate was then transferred to the growth chamber, where the temperature was raised to 570°C to remove the surface oxide layer. When the reflected high-energy electron diffraction (RHEED) pattern showed clear (1×3) reconstruction fringes, it indicated that the surface was clean.

[0066] A gallium antimonide (GaSb) buffer layer with a thickness of 100 nm was grown at 540 °C.

[0067] The substrate temperature was lowered to 460°C to begin growing a superlattice structure with a total of 50 periodic units.

[0068] The growth process of each cycle unit includes: growing a first indium arsenide (InAs) layer with a thickness of 3.7 nm.

[0069] Turn off the indium beam current source control unit, interrupt growth for 2 seconds (first interruption time), and keep the antimony beam current source control unit on.

[0070] Growth of a second InAs layer with a thickness of 0.35 nm 0.75 Sb 0.25 Strain compensation layer.

[0071] Turn off the indium beam source control unit and the arsenic beam source control unit, interrupt the growth for 3 seconds (second interruption time), and keep the antimony beam source control unit on.

[0072] Turn on the aluminum beam current source control component and grow a third aluminum antimonide (AlSb) barrier layer with a thickness of 1.2 nm.

[0073] Turn off the aluminum beam current source control component, interrupt growth for 3 seconds (third interruption time), and keep the antimony beam current source control component on.

[0074] Growth of a second InAs layer with a thickness of 0.35 nm 0.75 Sb 0.25 Strain compensation layer.

[0075] Turn off the indium beam source control unit and the arsenic beam source control unit, interrupt the growth for 3 seconds (fourth interruption time), and keep the antimony beam source control unit on.

[0076] After all 50 periodic units were grown, the samples were cooled to 245°C at a rate of 10°C / min under an antimony atmosphere before being removed.

[0077] Please refer to the X-ray diffraction (XRD) scan results of the above samples. Figure 2 As shown, the zero-order satellite peaks of the sample almost completely overlap with the characteristic diffraction peaks of the gallium antimonide substrate, and the satellite peaks are clear, sharp, and have a very small full width at half maximum (FWHM), indicating that the sample has high lattice matching and crystal quality. Figure 2 The vertical axis represents the diffraction intensity, with the unit being the number of diffracted photons per second; Figure 2 The horizontal axis represents the diffraction angle, in degrees.

[0078] Please refer to the atomic force microscopy (AFM) scan images of the above samples. Figure 3 As shown, select the entire scan area ( The scanning range is as follows: minimum height is -0.488 nm, maximum height is 0.604 nm, median height is 0.058 nm, surface roughness (RMS) of the above samples is less than 0.8 nm, atomic arrangement is regular, lattice integrity is high, and crystal quality is very high.

[0079] In summary, in the embodiments of this invention, by periodically introducing a compressive strain InAsSb layer of a specific composition into the indium arsenide / aluminum antimonide superlattice stack, the inherent tensile strain of the indium arsenide / aluminum antimonide superlattice itself is compensated, and the overall stress balance is achieved, thereby effectively suppressing lattice relaxation, significantly reducing dislocation density, and obtaining a superlattice material with excellent crystal quality.

[0080] Please refer to Figure 4 As shown, the present invention also provides an indium arsenide / aluminum antimonide superlattice structure, including an indium arsenide layer 41 and a first InAs... 1-x Sb x Strain compensation layer 42, aluminum antimonide barrier layer 43, second InAs 1-x Sb x Strain compensation layer 44. It can perform strain compensation on the indium arsenide / aluminum antimonide superlattice structure and the indium arsenide / aluminum antimonide superlattice composed of multiple such indium arsenide / aluminum antimonide superlattice structures, and ensure the performance of semiconductor devices based on the indium arsenide / aluminum antimonide superlattice.

[0081] Indium arsenide layer 41, first InAs 1-x Sb x Strain compensation layer 42, aluminum antimonide barrier layer 43, and second InAs 1-xSb x The strain compensation layers 44 are connected sequentially along the preset growth direction A.

[0082] First InAs 1-x Sb x Strain compensation layer 42 and second InAs 1-x Sb x The strain compensation layer 44 is the same.

[0083] First InAs 1-x Sb x The antimony composition x of the strain compensation layer 42 satisfies 0.1 ≤ x ≤ 0.4, and the first InAs 1-x Sb x The second thickness of the strain compensation layer 42 is greater than or equal to 0.2 nm and less than or equal to 2 nm.

[0084] The antimony component x, the second thickness, the first thickness of the indium arsenide layer 41, and the third thickness of the aluminum antimonide barrier layer 43 satisfy the equilibrium condition, which is that the total tensile strain in the indium arsenide / aluminum antimonide superlattice structure is equal to the total compressive strain.

[0085] Further explanation of the above-mentioned indium arsenide / aluminum antimonide superlattice structure can be understood by referring to the description of the strain-compensated growth method of the indium arsenide / aluminum antimonide superlattice. The embodiments of the present invention will not be repeated here.

[0086] It should be noted that the term "comprising" and its variations used in the embodiments of this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "a plurality" mentioned in the embodiments of this invention are illustrative and not restrictive, and those skilled in the art should understand that unless explicitly indicated otherwise in the context, they should be understood as "one or more". The descriptions of terms such as "first", "second", etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features.

[0087] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the embodiments of this invention are all information and data authorized by the user or fully authorized by all parties.

[0088] The steps described in the method embodiments provided by the present invention can be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0089] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0090] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A strain-compensated growth method for indium arsenide / aluminum antimonide superlattice, characterized in that, include: An indium arsenide layer of the first thickness is grown on the target substrate; A second InAs layer of a second thickness is grown on the indium arsenide layer. 1-x Sb x Strain compensation layer, wherein the InAs 1-x Sb x The antimony composition x of the strain compensation layer satisfies 0.1≤x≤0.4, and the second thickness is greater than or equal to 0.2nm and less than or equal to 2nm; In the InAs 1-x Sb x A third-thickness aluminum antimonide barrier layer is grown on the strain compensation layer; A layer of InAs is grown on the aluminum antimonide barrier layer. 1-x Sb x A strain compensation layer is formed to obtain periodic units, wherein the periodic units are composed of the indium arsenide layer and the InAs layer connected in sequence. 1-x Sb x The strain compensation layer, the aluminum antimonide barrier layer, and the InAs 1-x Sb x The superlattice structure composed of strain compensation layers, wherein the first thickness, the antimony composition x, the second thickness, and the third thickness satisfy an equilibrium condition, wherein the equilibrium condition is that the total tensile strain within the periodic unit is equal to the total compressive strain; A predetermined number of periodic units are sequentially grown on the periodic units to obtain an indium arsenide / aluminum antimonide superlattice.

2. The method according to claim 1, characterized in that, Growing an indium arsenide layer of first thickness on the target substrate, including: The target substrate is subjected to degassing and deoxidation treatments in sequence to obtain a pretreated substrate. A buffer layer is grown on the pretreated substrate; An indium arsenide layer of a first thickness is grown on the buffer layer.

3. The method according to claim 2, characterized in that, The target substrate is a gallium antimonide substrate, and the buffer layer is a gallium antimonide buffer layer; The target substrate is subjected to degassing and deoxidation treatments in sequence to obtain a pretreated substrate, including: The gallium antimonide substrate is placed into the pretreatment chamber of a molecular beam epitaxy apparatus, and the gallium antimonide substrate is degassed in a vacuum environment and at a first heating temperature to obtain a substrate to be deoxidized. The substrate to be deoxidized is placed into the growth chamber of the molecular beam epitaxy equipment, and the substrate to be deoxidized is subjected to deoxidation treatment in an antimony atmosphere protection environment and at a second heating temperature to obtain the pretreated substrate, wherein the second heating temperature is greater than the first heating temperature.

4. The method according to claim 3, characterized in that, The second heating temperature is 570±1℃; The gallium antimonide buffer layer is grown on the pretreated substrate at a growth temperature of 540~550℃, wherein the thickness of the gallium antimonide buffer layer is 100~300nm. Before growing an indium arsenide layer of a first thickness on the buffer layer, the method further includes adjusting the temperature of the pretreated substrate on which the buffer layer is grown to 455~475°C.

5. The method according to claim 1, characterized in that, A second InAs layer of a second thickness is grown on the indium arsenide layer. 1-x Sb x Prior to the strain compensation layer, the method further includes: Turn off the indium beam source control unit of the molecular beam epitaxy equipment, interrupt the growth during the first interruption time, and keep the antimony beam source control unit of the molecular beam epitaxy equipment open so that the antimony beam can surface wet the indium arsenide layer. In the InAs 1-x Sb x Before growing a third-thickness aluminum antimonide barrier layer on the strain compensation layer, the method further includes: The indium beam source control component and the arsenic beam source control component of the molecular beam epitaxy apparatus are turned off. Growth is interrupted during the second interruption time, while the antimony beam source control component remains on, so that the antimony beam current is directed onto the InAs grown on the indium arsenide layer. 1-x Sb x The strain compensation layer is surface-wetted. A layer of InAs is grown on the aluminum antimonide barrier layer. 1-x Sb x Prior to the strain compensation layer, the method further includes: The aluminum beam current source control component of the molecular beam epitaxy equipment is turned off, the growth is interrupted during the third interruption time, and the antimony beam current source control component is kept on so that the antimony beam current wets the surface of the aluminum antimonide barrier layer. A layer of InAs is grown on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic elements from the strain compensation layer, the method further includes: The indium beam source control component and the arsenic beam source control component are turned off. Growth is interrupted during the fourth interruption time, while the antimony beam source control component remains on, so that the antimony beam current can be directed onto the InAs grown on the aluminum antimonide barrier layer. 1-x Sb x The strain compensation layer is surface-wetted. The first interrupt time, the second interrupt time, the third interrupt time, and the fourth interrupt time are all greater than or equal to 1 second and less than or equal to 10 seconds.

6. The method according to claim 1, characterized in that, A layer of InAs is grown on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic elements from the strain compensation layer, the method further includes: X-ray diffraction scanning was performed on the periodic unit to obtain the first scanning result; If the first scan result does not meet the first preset condition, adjust the InAs 1-x Sb x The antimony composition x and the second thickness of the strain compensation layer are used to grow new periodic cells on the target substrate.

7. The method according to claim 6, characterized in that, A layer of InAs is grown on the aluminum antimonide barrier layer. 1-x Sb x After obtaining the periodic elements from the strain compensation layer, the method further includes: The periodic unit was scanned using an atomic force microscope to obtain a second scanning result; If the first scan result does not meet the first preset condition, and / or the second scan result does not meet the second preset condition, adjust the InAs. 1-x Sb x The antimony composition x and the second thickness of the strain compensation layer are used to grow the new periodic unit on the target substrate.

8. The method according to claim 7, characterized in that, The first preset condition is that the zero-order satellite peak of the periodic unit coincides with the characteristic diffraction peak of the target substrate; the second preset condition is that the periodic unit in The surface roughness within the scanning range is less than 0.8 nm.

9. The method according to claim 1, characterized in that, The preset quantity is 49, and the total number of the periodic units is 50; After sequentially growing a predetermined number of periodic units on the periodic units to obtain an indium arsenide / aluminum antimonide superlattice, the method further includes: Under an antimony atmosphere, the temperature of the indium arsenide / aluminum antimonide superlattice was adjusted to less than 250°C before it was removed.

10. An indium arsenide / aluminum antimonide superlattice structure, characterized in that, Including indium arsenide layer, first InAs 1-x Sb x Strain compensation layer, aluminum antimonide barrier layer, second InAs 1-x Sb x Strain compensation layer; The indium arsenide layer, the first InAs 1-x Sb x The strain compensation layer, the aluminum antimonide barrier layer, and the second InAs 1- x Sb x The strain compensation layers are connected sequentially along a preset growth direction; First InAs 1-x Sb x Strain compensation layer and the second InAs 1-x Sb x The strain compensation layer is the same; First InAs 1-x Sb x The antimony composition x of the strain compensation layer satisfies 0.1 ≤ x ≤ 0.4, and the first InAs 1-x Sb x The second thickness of the strain compensation layer is greater than or equal to 0.2 nm and less than or equal to 2 nm; The antimony component x, the second thickness, the first thickness of the indium arsenide layer, and the third thickness of the aluminum antimonide barrier layer satisfy an equilibrium condition, wherein the equilibrium condition is that the total tensile strain within the indium arsenide / aluminum antimonide superlattice structure is equal to the total compressive strain.

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