A method and apparatus for molecular beam epitaxial growth of heterointerfaces
By coordinating and controlling the movement of the source material using an electron beam and an electromagnetic control system, the problems of prolonged growth time and reliability of heterostructures in molecular beam epitaxy have been solved, achieving efficient and precise heterostructure control and improving device performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGDONG TRUEONE SEMICON TECH CO LTD
- Filing Date
- 2021-09-11
- Publication Date
- 2026-06-05
AI Technical Summary
In existing molecular beam epitaxy technology, the rapid switching and frequent movement of the movable baffle leads to prolonged growth time and mechanical reliability issues for heterogeneous interfaces, making it difficult to achieve high-precision and efficient heterogeneous interface control.
By employing an electron beam control system and an electromagnetic control system, the movement direction of the source material is controlled through electron emission and local electric or magnetic fields, enabling non-mechanical heterostructure growth. Combined with the coordinated control of the electron beam and electromagnetic control systems, the structure, composition, or doping concentration of the heterostructure can be rapidly controlled.
This technology enables high-precision and efficient control of heterogeneous interface materials, improves the quality of heterogeneous interfaces, simplifies device structure design, and enhances the reliability and efficiency of molecular beam epitaxy.
Smart Images
Figure CN115807263B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of thin film preparation technology, and specifically relates to a method and apparatus for heterogeneous interface growth in molecular beam epitaxy. Background Technology
[0002] In recent years, with the development of semiconductor device applications, people have been constantly trying to design various new device structures to improve device performance. Interface manipulation of heterojunctions is crucial to the performance of semiconductor devices, such as quantum wells for lasers, tunnel junctions for multi-junction photovoltaic cells, photonic crystals, and metamaterials. Steep interface composition or doping concentration often yields significant performance improvements, which makes device design increasingly demanding in terms of process technology.
[0003] Molecular beam epitaxy (MBE) is a high-precision thin film fabrication technique. The source material is heated and emitted in a source furnace and deposited on a substrate. The source material is rapidly emitted and blocked by a movable baffle installed at the source furnace exit, thereby obtaining a high-precision heterostructure. However, the control of the movable baffle's motion mechanism has two aspects. First, there is a time delay in opening and closing, which means that the time to grow an ultrathin heterostructure must be extended to eliminate the effect of the time delay of the movable baffle. Second, frequent movement can also easily lead to reliability issues.
[0004] Therefore, designing a non-mechanical method to control the flow rate of the source material to the substrate can significantly improve the quality of existing heteromaterial interfaces and enable the fabrication of previously difficult-to-manufacture device structures through novel processes. This is crucial for the development and application of molecular beam epitaxy (MBE). Summary of the Invention
[0005] This invention provides a method and apparatus for growing heterostructures using molecular beam epitaxy, which solves the process and mechanical reliability problems caused by rapidly switching sources via baffles during the heterostructure growth process in existing molecular beam epitaxy technology.
[0006] First, the present invention provides a method for growing heterostructures via molecular beam epitaxy through an implementation example, the method comprising the following steps.
[0007] Step 1: Heat the source furnace to form a source material molecular beam, and grow a uniform thin film material on the substrate.
[0008] Step 2: When the heterogeneous interface thin film layer is about to grow, turn on the electron beam control system and the electromagnetic control system.
[0009] Step 3: Based on the structural changes of the heterojunction thin film to be prepared and the changes in the composition or doping concentration gradient of the material, the electron emission gun in the electron beam control system emits electrons at a certain duty cycle frequency. When the electron emission gun in the electron beam control system emits electrons, the emitted electrons encounter the source material molecular beam, causing the atomic group particles of the source material molecular beam to become charged, and the excess electrons that are not attached to the atomic group particles of the source material molecular beam reach the electron beam receiving screen.
[0010] Step 4: Based on the structural changes of the heterogeneous interface thin film to be prepared and the changes in the composition or doping concentration gradient of the material, the electromagnetic control system generates a local electric field or local magnetic field between the source furnace and the substrate at a certain duty cycle frequency. When the electromagnetic control system generates a local electric field or local magnetic field between the source furnace and the substrate, the charged atomic group particles of the source material molecular beam are subjected to electromagnetic force in the local electric field or local magnetic field, and their motion direction is deflected, reaching the charged particle receiving screen. When the electromagnetic control system does not generate a local electric field or local magnetic field between the source furnace and the substrate, the charged atomic group particles of the source material molecular beam reach the substrate surface in their original motion direction.
[0011] Step 5: Turn off the electron beam control system and the electromagnetic control system, and continue to grow a uniform thin film material on the substrate.
[0012] Furthermore, in step three, the electron emission gun in the electron beam control system emits electrons at a certain duty cycle frequency. Depending on the interface structure of the grown device or the characteristics of the source material, the intensity of the emitted electrons can change in the form of a square wave or a triangular wave.
[0013] Furthermore, in step four, the electromagnetic control system generates a local electric field or a local magnetic field between the source furnace and the substrate at a certain duty cycle frequency. The direction of the generated local electric field or local magnetic field is perpendicular to the direction of motion of the atomic group particles of the molecular beam source flow.
[0014] Furthermore, depending on the interface structure of the grown device or the characteristics of the source material, the intensity change of the generated local electric field or local magnetic field can be a square wave or a triangular wave, and the intensity waveform of the local electric field or local magnetic field generated by the electromagnetic control system has the same frequency as the intensity waveform of the electron beam generated by the electron beam control system, with a phase delay of 180°.
[0015] Furthermore, the present invention provides an apparatus for growing heterostructures using molecular beam epitaxy. An electron beam control system and an electromagnetic control system are sequentially arranged between the source furnace and the substrate. The electron beam control system includes an electron beam emitting gun and an electron beam receiving screen. A charged particle receiving screen is installed at the bottom of the molecular beam epitaxy apparatus.
[0016] When applying the molecular beam epitaxy (MBE) technique for growing heterointerfaces according to this invention, the duty cycle frequencies of the electron beam control system and the electromagnetic control system need to be rationally set according to the structural changes of the heterointerface film to be prepared and the changes in the composition or doping concentration gradient of the material, thereby achieving coordinated control between the electron beam control system and the electromagnetic control system. This invention achieves control over the composition or doping concentration of the heterointerface material in a non-mechanical manner, with a very rapid control rate. By programming and controlling the electron beam control system and the electromagnetic control system, complex and diverse heterointerface structures can be achieved. Attached Figure Description
[0017] Figure 1 This is a schematic side view showing the structure of a molecular beam epitaxy growth apparatus according to the present invention. Figure 2 This is a schematic top view showing the structure of a molecular beam epitaxy growth apparatus according to the present invention.
[0018] Explanation of reference numerals in the attached figures: 101 Molecular beam epitaxy device housing; 102 Substrate tray shaft; 103 Substrate tray; 104 Substrate; 210 Electromagnetic control system one; 220 Electromagnetic control system two; 310 Electron beam control system one; 320 Electron beam control system two; 410 Source furnace one; 420 Source furnace two; 501 Charged particle receiving screen; 311 Electron beam receiving screen one; 312 Electron beam emitting gun one; 321 Electron beam receiving screen two; 322 Electron beam emitting gun two. Detailed Implementation
[0019] Example: After cleaning and drying the sapphire substrate with nitrogen, it is placed in the sample inlet chamber of a molecular beam epitaxy (MBE) apparatus. After a 1-hour high-temperature pretreatment, the sapphire substrate is transferred to the substrate tray 103 in the growth chamber of the MBE apparatus. When the chamber vacuum reaches the required growth level, the Ga source furnace 410 is heated to form a Ga source material molecular beam, and an N source is injected into the chamber to grow a uniform GaN thin film on the substrate 104. Just before the GaN / InGaN quantum well is about to grow, the In source furnace 420 is heated, and the electron beam control system 320 and the electromagnetic control system 220 are activated. The electron emission gun 322 in the electron beam control system 320 between the In source furnace 420 and the substrate emits electrons. These emitted electrons encounter the In source material molecular beam, causing the atomic groups of the In source material molecular beam to become charged. Excess electrons not attached to the atomic groups of the In source material molecular beam reach the electron beam receiving screen 321. Electromagnetic control system 220, located between electron beam control system 320 and substrate 104, generates a local magnetic field with an 80% duty cycle. The magnetic field strength is a square wave, with each cycle lasting 20 seconds, for a total of 5 cycles. When electromagnetic control system 220 generates a local magnetic field between In source furnace 420 and substrate 104, the atomic group particles of the charged In source material molecular beam are subjected to electromagnetic force in the local magnetic field, causing their motion direction to deflect and reach the charged particle receiving screen 501. When electromagnetic control system 220 does not generate a local magnetic field between In source furnace 420 and substrate 104, the atomic group particles of the In source material molecular beam reach the surface of substrate 104 in their original motion direction. Electron beam control system 320 and electromagnetic control system 420 are then turned off, and uniform GaN thin film material continues to grow on substrate 104.
[0020] The above embodiments mainly illustrate the method of growing heterointerfaces using the molecular beam epitaxy (MBE) heterointerface growing apparatus proposed in this invention. Although only one embodiment of the invention has been described, the invention can be implemented in many other ways without departing from its spirit and scope. Therefore, it should be understood that the above embodiments are not limited to this invention, and all modifications and substitutions made within the spirit and principles of this invention should be included within the protection scope of this invention.
Claims
1. A method for growing heterointerfaces using molecular beam epitaxy, wherein, It includes the following steps: Step 1: Heat the source furnace to form a molecular beam of source material, and grow a uniform thin film material on the substrate; Step 2: When the heterogeneous interface thin film layer is about to grow, turn on the electron beam control system and the electromagnetic control system; Step 3: Based on the structural changes of the heterojunction thin film to be prepared and the changes in the composition or doping concentration gradient of the material, the electron emission gun in the electron beam control system emits electrons at a certain duty cycle frequency. Step 4: Based on the structural changes of the heterogeneous interface film to be prepared and the changes in the composition or doping concentration gradient of the material, the electromagnetic control system generates a local electric field or a local magnetic field between the source furnace and the substrate at a certain duty cycle frequency. Step 5: Turn off the electron beam control system and the electromagnetic control system, and continue to grow a uniform thin film material on the substrate.
2. The method for growing heterointerfaces by molecular beam epitaxy according to claim 1, characterized in that, The intensity change of the emitted electrons in step three can be a square wave or a triangular wave, etc.
3. The method for growing heterointerfaces by molecular beam epitaxy according to claim 1, characterized in that, The local electric field or local magnetic field generated in step four is perpendicular to the direction of motion of the atomic group particles of the molecular beam source flow.
4. The method for growing heterointerfaces by molecular beam epitaxy according to claim 1, characterized in that, Depending on the interface structure of the grown device or the characteristics of the source material, the intensity change of the local electric field or local magnetic field generated in step four can be a square wave or a triangular wave, and the intensity waveform of the local electric field or local magnetic field generated by the electromagnetic control system has the same frequency as the intensity waveform of the electron beam generated by the electron beam control system, with a phase delay of 180°.
5. An apparatus for growing heterostructures using the method of molecular beam epitaxy as described in claim 1, characterized in that, Between the source furnace and the substrate are an electron beam control system and an electromagnetic control system. The electron beam control system includes an electron beam emitting gun and an electron beam receiving plate. A charged particle receiving screen is installed at the bottom of the molecular beam epitaxy device.