Monocrystalline thin film with ultra-high activation doping concentration, preparation method and application thereof
By controlling the temperature and growth conditions of the boron source thermal evaporation crucible using molecular beam epitaxy, ultra-high activation doping concentration Si:B and Si1-xGex:B single crystal thin films were prepared, solving the problem of high metal-semiconductor contact resistivity in existing technologies and improving the performance of silicon-based integrated circuit devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INSTITUTE OF PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-12-02
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies make it difficult to prepare single-crystal thin films of Si:B and SiGe:B with ultra-high activation doping concentrations, resulting in high metal-semiconductor contact resistivity, which limits the improvement of silicon-based integrated circuit device performance.
In-situ heat treatment and growth were performed in the molecular beam epitaxy cavity using molecular beam epitaxy technology. By controlling the temperature of the boron source thermal evaporation crucible, the growth temperature, and the growth rate, Si:B and Si1-xGex:B single crystal thin films with ultra-high activation doping concentrations were prepared.
The active doping concentration of B in Si:B single crystal thin films reached 2.2×1021cm-3, and the active doping concentration of B in Si1-xGex:B single crystal thin films reached 2.7×1021cm-3, which significantly reduced the metal-semiconductor contact resistivity and improved the performance of silicon-based integrated circuit devices.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of materials science. Specifically, this invention relates to a single-crystal thin film with ultra-high activation doping concentration, its preparation method, and its applications. Background Technology
[0002] As device dimensions shrink in silicon-based integrated circuits, the source-drain contact area continuously decreases, making metal-semiconductor contact resistance a major component of device extended resistance. Improvements in device performance are limited by this contact resistance. To achieve low-resistance contacts, fabricating doped layers with ultra-high activation doping concentrations has become an important approach. This effectively reduces the contact barrier height at the metal-semiconductor interface, thereby achieving interface matching in the energy band. Ion implantation doping requires a high thermal budget to activate impurities and cannot achieve uniform doping; therefore, in-situ doping is more suitable for device integration in integrated circuits.
[0003] Currently, the boron activation doping concentration is higher than 2×10⁻⁶. 20 cm -3 Si 1-x Ge x Boron (x>35%) can achieve low sheet resistance source / drain regions and apply the required compressive strain in the channel, making it the optimal material for source / drain epitaxy in advanced technology nodes. However, integrating single-crystal Si(SiGe):B films with ultra-high activation doping concentrations presents significant challenges. On one hand, the maximum solid solubility of boron in silicon and germanium are 4 × 10⁻⁶, respectively. 20 cm -3 and 2×10 18 cm -3 Under thermal equilibrium growth conditions, the active doping concentration of Si(SiGe):B thin films is limited by solid solubility. On the other hand, the high temperature of traditional epitaxial processes and the "competitive effect" between germanium and boron can lead to boron segregation, making it difficult to achieve higher doping concentrations.
[0004] Current technologies generally use SiH₂Cl₂ and GeH₄ as precursors for silicon and germanium, respectively, and employ chemical vapor deposition (CVD) to in-situ epitaxially grow highly doped Si(SiGe):B materials. Related reports indicate that in-situ doped Si:B thin films grown at 600℃-700℃ have a chemical doping concentration of 3×10⁻⁶. 21 cm -3 The activation doping concentration is only 8×10 19 cm -3 To increase the boron activation doping concentration in Si(SiGe):B, related studies have employed low growth temperatures (500℃-550℃) to enhance the boron activation doping concentration in Si grown via CVD. 0.85 Ge 0.15 :B and Si 0.5 Ge 0.5:B thin films achieved 5×10 20 cm -3 and 1×10 21 cm -3 The activation doping concentration was determined. Furthermore, considering that gallium's solid solubility in germanium is two orders of magnitude greater than that of boron, related studies employed a gallium-boron co-doping method, obtaining an average activation doping concentration of 1.2 × 10⁻⁶. 21 cm -3 Si 0.5 Ge 0.5 (Ga+B) thin film.
[0005] Therefore, there is an urgent need for a method to prepare Si:B single crystal thin films and SiGe:B single crystal thin films with ultra-high activation doping concentration, which can reduce the resistivity of metal-semiconductor contacts and thus achieve low-resistance contacts in integrated circuits. Summary of the Invention
[0006] To reduce the resistivity of metal-semiconductor contacts and thereby improve the performance of devices in silicon-based integrated circuits, one of the objectives of this invention is to provide a Si:B single-crystal thin film with an ultra-high activation doping concentration.
[0007] Another object of the present invention is to provide a Si with an ultra-high activation doping concentration. 1-x Ge x :B Single crystal thin film.
[0008] Another object of the present invention is to provide a method for preparing the Si:B single crystal thin film or Si of the present invention. 1-x Ge x Methods for single-crystal thin films: B.
[0009] The above-mentioned objective of the present invention is achieved through the following technical solution.
[0010] In a first aspect, the present invention provides a Si:B single-crystal thin film with ultra-high activation doping concentration, wherein the activation doping concentration of B is at least 1.5 × 10⁻⁶. 21 cm -3 .
[0011] Preferably, in the Si:B single crystal thin film with ultra-high activation doping concentration described in this invention, the thickness of the Si:B single crystal thin film is 10-200 nm, more preferably 10-50 nm, and even more preferably 20 nm.
[0012] In a second aspect, the present invention provides a silicon-based composite structure comprising:
[0013] silicon substrate,
[0014] A silicon buffer layer located on the silicon substrate, and
[0015] An ultra-high activation doping concentration Si:B single crystal thin film located on the silicon buffer layer;
[0016] The activation doping concentration of B is at least 1.5 × 10⁻⁶. 21 cm -3 .
[0017] Preferably, in the silicon-based composite structure of the present invention, the thickness of the Si:B single crystal thin film is 10-200 nm, more preferably 10-50 nm, and even more preferably 20 nm.
[0018] Thirdly, the present invention provides a method for preparing a Si:B single crystal thin film with ultra-high activation doping concentration as described in the present invention, which sequentially includes the following steps performed in a molecular beam epitaxy cavity:
[0019] (1) Perform in-situ heat treatment on the silicon substrate;
[0020] (2) A silicon buffer layer is grown on the silicon substrate after heat treatment in step (1);
[0021] (3) A Si:B single crystal thin film with ultra-high activation doping concentration is epitaxially grown on the surface of the silicon buffer layer;
[0022] (4) Optionally, a silicon capping layer is epitaxially grown on the Si:B single crystal thin film with ultra-high activation doping concentration;
[0023] In step (3), the epitaxial growth of a Si:B single crystal thin film with ultra-high activation doping concentration on the surface of the silicon buffer layer is carried out under the following conditions: the temperature of the boron source thermal evaporation crucible is 1900-2050℃, preferably 2000-2050℃.
[0024] Preferably, in the method for preparing Si:B single crystal thin films with ultra-high activation doping concentration of the present invention, the epitaxial growth of Si:B single crystal thin films with ultra-high activation doping concentration on the surface of the silicon buffer layer in step (3) is carried out at a growth temperature of 300-600°C, more preferably 350°C.
[0025] Preferably, in the method for preparing a Si:B single crystal thin film with ultra-high activation doping concentration according to the present invention, the epitaxial growth of the Si:B single crystal thin film with ultra-high activation doping concentration on the surface of the silicon buffer layer in step (3) is carried out at a silicon growth rate of [missing information]. It was carried out under certain conditions.
[0026] Preferably, in the preparation method of the Si:B single crystal thin film with ultra-high activation doping concentration of the present invention, the in-situ heat treatment of the silicon substrate in step (1) is carried out by a method including the following steps: heating the silicon substrate to 400-550°C for annealing for 5-30 minutes, and then heating it to 600-750°C for annealing for 5-30 minutes.
[0027] Preferably, in the method for preparing Si:B single crystal thin films with ultra-high activation doping concentration of the present invention, the growth of a silicon buffer layer on the silicon substrate after heat treatment in step (1) in step (2) is carried out by a method including the following steps: growing a silicon buffer layer on the silicon substrate at 300-600°C using molecular beam epitaxy at molecular beam epitaxy.
[0028] Preferably, in the method for preparing the ultra-high activation doping concentration Si:B single crystal thin film of the present invention, the epitaxial growth of the silicon capping layer on the ultra-high activation doping concentration Si:B single crystal thin film in step (4) is carried out under the following conditions: the growth temperature is 200-350℃, and the Si growth rate is...
[0029] Fourthly, the present invention provides a Si with an ultra-high activation doping concentration. 1-x Ge x :B single-crystal thin film, wherein 0.25≤x≤0.4, and the active doping concentration of B is at least 1.5×10⁻⁶. 21 cm -3 .
[0030] Preferably, in the Si with ultra-high activation doping concentration described in this invention 1-x Ge x In B single-crystal thin films, the Si 1- x Ge x The thickness of the B single crystal thin film is 10-200 nm, preferably 10-50 nm, and more preferably 20 nm.
[0031] Fifthly, the present invention provides a silicon-based composite structure comprising:
[0032] silicon substrate,
[0033] A silicon buffer layer located on the silicon substrate, and
[0034] The ultra-high activation doping concentration of Si located above the silicon buffer layer 1-x Ge x :B Single crystal thin film;
[0035] The activation doping concentration of B is at least 1.5 × 10⁻⁶. 21 cm -3 .
[0036] Preferably, in the silicon-based composite structure of the present invention, the Si 1-x Ge x The thickness of the single-crystal thin film is 10-200 nm, more preferably 10-50 nm, and even more preferably 20 nm.
[0037] Sixthly, the present invention provides a method for preparing Si with ultra-high activation doping concentration according to the present invention. 1-x Ge x The method for producing single-crystal thin films includes the following steps performed sequentially in a molecular beam epitaxy cavity:
[0038] (1) Perform in-situ heat treatment on the silicon substrate;
[0039] (2) A silicon buffer layer is grown on the silicon substrate after heat treatment in step (1);
[0040] (3) Epitaxially growing Si with ultra-high activation doping concentration on the surface of the silicon buffer layer. 1-x Ge x :B Single crystal thin film;
[0041] (4) Optionally, in the ultra-high activation doping concentration of Si 1-x Ge x :B. Epitaxial growth of a silicon capping layer on a single-crystal thin film;
[0042] In step (3), an ultra-high activation doping concentration Si is epitaxially grown on the surface of the silicon buffer layer. 1- x Ge x The single-crystal thin film evaporation was carried out under the following conditions: the temperature of the boron source thermal evaporation crucible was 1900-2050℃, preferably 2000-2050℃.
[0043] Preferably, in the Si with ultra-high activation doping concentration of the present invention 1-x Ge x In the method for preparing single-crystal thin films, step (3) involves epitaxially growing Si with an ultra-high activation doping concentration on the surface of the silicon buffer layer. 1-x Ge x The single-crystal thin film was grown at a temperature of 300-600℃, more preferably 300℃.
[0044] Preferably, in the Si with ultra-high activation doping concentration of the present invention 1-x Ge x In the method for preparing single-crystal thin films, step (3) involves epitaxially growing Si with an ultra-high activation doping concentration on the surface of the silicon buffer layer. 1-x Ge x:B Single-crystal thin films are produced when silicon grows at a rate of And the growth rate of germanium is It was carried out under certain conditions.
[0045] Preferably, in the Si with ultra-high activation doping concentration of the present invention 1-x Ge x In the preparation method of single crystal thin film, the in-situ heat treatment of silicon substrate in step (1) is carried out by a method including the following steps: heating the silicon substrate to 400-550℃ for annealing for 5-30 minutes, and then heating it to 600-750℃ for annealing for 5-30 minutes.
[0046] Preferably, in the Si with ultra-high activation doping concentration of the present invention 1-x Ge x In the preparation method of single crystal thin film, the growth of silicon buffer layer on the silicon substrate after heat treatment in step (1) in step (2) is carried out by a method including the following steps: growing silicon buffer layer on the silicon substrate at 300-600℃ using molecular beam epitaxy.
[0047] Preferably, in the Si with ultra-high activation doping concentration of the present invention 1-x Ge x In the preparation method of single-crystal thin films, step (4) involves using Si with an ultra-high activation doping concentration. 1-x Ge x The epitaxial growth of a silicon capping layer on a single-crystal thin film was carried out under the following conditions: growth temperature of 200-350℃, and Si growth rate of...
[0048] In some specific embodiments of the present invention, the resistivity of the silicon substrate used for epitaxy is greater than 20000 Ω·cm, and the crystal plane is (100).
[0049] In a seventh aspect, the present invention provides a Si:B single crystal thin film with ultra-high activation doping concentration, a silicon-based composite structure, or a Si with ultra-high activation doping concentration. 1-x Ge x Applications of single-crystal thin films in silicon-based integrated circuit devices.
[0050] In specific embodiments of the present invention, the silicon-based integrated circuit device may be, for example, a CMOS device, a FinFET device, or a GAA device.
[0051] In the Si:B single crystal thin film or Si of the present invention 1-x Ge xIn the preparation method of :B single crystal thin films, the temperature of the boron thermal evaporation crucible is 1900-2050℃. If it is below 1900℃, the amount of doped atoms evaporated is low, and the activation doping concentration is also limited accordingly; if it exceeds 2050℃, the equipment requirements are too high, making it difficult to achieve.
[0052] In the Si:B single crystal thin film or Si of the present invention 1-x Ge x In the preparation method of :B single crystal thin films, the growth temperature is 300-600℃. Below 300℃, the crystal quality is low or even polycrystalline amorphous is formed; above 600℃, thermal equilibrium growth is achieved, and the increase in activation doping concentration is limited by the solid solubility of the dopant element in silicon and silicon-germanium.
[0053] In the Si:B single crystal thin film or Si of the present invention 1-x Ge x In the preparation method of single-crystal thin films, the silicon growth rate is... If the growth rate of silicon is The following requirements place excessive demands on the equipment and are too stringent to meet; greater than A low silicon growth rate leads to a lower boron content in the thin film and a lower concentration of activated dopant.
[0054] In the Si of the present invention 1-x Ge x In the preparation method of B single crystal thin film, the germanium growth rate is... If the growth rate of germanium is at The following requirements place excessive demands on the equipment and are too stringent to meet; greater than The germanium growth rate leads to a decrease in the proportion of boron in the thin film and a low concentration of activated doping.
[0055] The present invention has the following beneficial effects:
[0056] The Si:B single crystal thin film or Si prepared by the method of the present invention 1-x Ge x Si:B single-crystal thin films possess extremely high activation doping concentrations. In Si:B single-crystal thin films or Si... 1-x Ge x In B single-crystal thin films, the active doping concentration of B is at least 1.5 × 10⁻⁶. 21 cm -3 In Si:B single-crystal thin films, the active doping concentration of B reached 2.2 × 10⁻⁶. 21 cm -3 In Si 1-x Ge x In the boron single-crystal thin film, the active doping concentration of boron reached 2.7 × 10⁻⁶. 21 cm -3The single-crystal thin film with ultra-high activation doping concentration of this invention can significantly reduce the resistivity of metal-semiconductor contacts, thereby improving the performance of devices in silicon-based integrated circuits.
[0057] The ultra-high activation doping concentration single-crystal thin film provided by this invention has high crystal quality, atomically smooth surface, and an electrical activation concentration that exceeds the solid solubility of boron in silicon and silicon-germanium alloys by an order of magnitude, which is the highest value of electrical activation concentration reported to date. Attached Figure Description
[0058] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:
[0059] Figure 1 The activated doping concentration prepared in Example 1 of this invention is 2.2 × 10⁻⁶. 21 cm -3 Atomic force microscopy image of the surface of a single-crystal Si:B thin film;
[0060] Figure 2 The activated doping concentration prepared in Example 1 of this invention is 2.2 × 10⁻⁶. 21 cm -3 High-resolution transmission electron microscope image of a cross-section of a single-crystal Si:B thin film;
[0061] Figure 3 The activated doping concentration prepared in Example 1 of this invention is 2.2 × 10⁻⁶. 21 cm -3 Secondary ion mass spectrum of single-crystal Si:B thin film;
[0062] Figure 4 The activated doping concentration prepared in Example 2 of this invention is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B Surface atomic force microscopy image of the thin film;
[0063] Figure 5 The activated doping concentration prepared in Example 2 of this invention is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B. High-resolution transmission electron microscope image of the cross-section of the thin film;
[0064] Figure 6 The activated doping concentration prepared in Example 3 of this invention is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.63 Ge 0.37 :B Surface atomic force microscopy image of the thin film;
[0065] Figure 7 The activated doping concentration prepared in Example 3 of this invention is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.63 Ge 0.37 :B. High-resolution transmission electron microscope image of the cross-section of the thin film;
[0066] Figure 8 These are secondary ion mass spectra of the ultra-high activation doping concentration single-crystal thin films prepared in Examples 2 and 3 of this invention;
[0067] Figure 9 The activated doping concentration prepared in Example 4 of this invention is 1.8 × 10⁻⁶. 21 cm -3 Atomic force microscopy image of the surface of a single-crystal Si:B thin film;
[0068] Figure 10 The activated doping concentration prepared in Example 5 of this invention is 2.0 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B Surface atomic force microscopy image of the thin film;
[0069] Figure 11 The activated doping concentration prepared in Example 6 of this invention is 1.5 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B Surface atomic force microscopy image of the thin film;
[0070] Figure 12 This is a schematic diagram of the Hall effect test used in the embodiments of the present invention;
[0071] Figure 13 This is a summary of data calculated by Hall effect testing in this embodiment of the invention to determine the activation doping concentration. Detailed Implementation
[0072] The present invention will be further described in detail below with reference to specific embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.
[0073] It should be noted that the following embodiments use a Hall effect meter to measure the concentration of activated doping in the sample, and the specific method is as follows:
[0074] Four-inch Si:B / Si obtained using molecular beam epitaxy 1-x Ge xAfter sample B, take a 1cm x 1cm small sample from both the edge and center regions of the sample, and place the indium electrode at each of the four corners. Then proceed as follows: Figure 12 The Hall test shown obtains the Hall voltage after error elimination by changing the direction of the magnetic field and current. Changing the current magnitude yields three Hall voltages under different currents. The average Hall voltage is then obtained by averaging the Hall voltages of small samples taken from the central and edge regions. The thickness of the doped layer is measured using a transmission electron microscope. The activation doping concentration of the sample can be calculated from the measured average Hall voltage and the doped layer thickness. The activation doping concentration data in the example are as follows: Figure 13 As shown.
[0075] Example 1
[0076] This embodiment illustrates that the activation doping concentration of the present invention is 2.2 × 10⁻⁶. 21 cm -3 Single-crystal Si:B thin films and their preparation methods are described. Specifically, the preparation method of single-crystal Si:B thin films includes the following steps:
[0077] (1) Immerse the silicon (100) substrate for 1 minute using a 5% hydrofluoric acid solution.
[0078] (2) Anneal the silicon (100) substrate at 400°C for 10 minutes in the molecular beam epitaxy cavity, and then heat it to 680°C for 10 minutes.
[0079] (3) A 50 nm silicon buffer layer was epitaxially grown on the heat-treated silicon substrate using molecular beam epitaxy (MBE) at a growth rate of [missing information]. The growth temperature is 400℃, then the temperature is lowered to 350℃ for annealing for 5 minutes.
[0080] (4) A 20 nm ultra-high activation doping concentration single-crystal Si:B thin film was epitaxially grown on the above-mentioned silicon buffer layer using molecular beam epitaxy (MBE) technology, with a silicon growth rate of [missing information]. The growth temperature was 350℃, the boron crucible temperature was 2000℃, and then the temperature was lowered to 300℃ for annealing for 2 minutes.
[0081] (5) A 1 nm silicon capping layer was grown on the above-mentioned ultra-high activation doping concentration single-crystal Si:B thin film using molecular beam epitaxy, at a growth rate of [missing information]. The growth temperature is 300℃.
[0082] Depend on Figure 1 It can be seen that the activation doping concentration in Example 1 is 2.2 × 10⁻⁶. 21 cm -3 The surface of the single-crystal Si:B thin film sample is flat and has no three-dimensional structure.
[0083] Depend on Figure 2It can be seen that the activation doping concentration in Example 1 is 2.2 × 10⁻⁶. 21 cm -3 The single-crystal Si:B thin film has an ordered lattice arrangement and is a high-quality single-crystal structure.
[0084] Depend on Figure 3 It can be seen that the activation doping concentration in Example 1 is 2.2 × 10⁻⁶. 21 cm -3 The single-crystal Si:B thin film is chemically uniformly doped along the depth direction, with an average chemical doping concentration of 3.6 × 10⁻⁶. 21 cm -3 This indicates that the electrical activation rate is approximately 58%.
[0085] Example 2
[0086] This embodiment illustrates that the activation doping concentration of the present invention is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B Thin films and their preparation methods. Specifically, single-crystal Si 0.72 Ge 0.28 The preparation method of :B thin film includes the following steps:
[0087] (1) Immerse the silicon (100) substrate for 1 minute using a 5% hydrofluoric acid solution.
[0088] (2) Anneal the silicon (100) substrate at 400°C for 10 minutes in the molecular beam epitaxy cavity, and then heat it to 680°C for 10 minutes.
[0089] (3) A 50 nm silicon buffer layer was epitaxially grown on the heat-treated silicon substrate using molecular beam epitaxy (MBE) at a growth rate of [missing information]. The growth temperature is 400℃, then the temperature is lowered to 300℃ for annealing for 5 minutes.
[0090] (4) A 20nm ultra-high activation doping concentration single-crystal Si was epitaxially grown on the above-mentioned silicon buffer layer using molecular beam epitaxy. 0.72 Ge 0.28 :B thin film, silicon growth rate is Germanium growth rate is The growth temperature was 300℃, and the boron crucible temperature was 2050℃.
[0091] (5) Molecular beam epitaxy is used to grow single-crystal Si with ultra-high activation doping concentration. 0.72 Ge 0.28 A 1nm silicon capping layer is grown on a thin film at a growth rate of . The growth temperature is 300℃.
[0092] Depend on Figure 4 It can be seen that the activation doping concentration in Example 2 is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B The surface of the thin film sample is flat and has no three-dimensional structure.
[0093] Depend on Figure 5 It can be seen that the activation doping concentration in Example 2 is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B Thin film has an ordered lattice arrangement, which is a good single crystal structure.
[0094] Depend on Figure 8 It can be seen that the activation doping concentration in Example 2 is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 The average germanium content of the B film is 28%, and the chemical distribution is relatively uniform along the depth direction.
[0095] Example 3
[0096] This embodiment illustrates that the activation doping concentration of the present invention is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.63 Ge 0.37 :B Thin films and their preparation methods. Specifically, single-crystal Si 0.63 Ge 0.37 The preparation method of :B thin film includes the following steps:
[0097] (1) Immerse the silicon (100) substrate for 1 minute using a 5% hydrofluoric acid solution.
[0098] (2) Anneal the silicon (100) substrate at 400°C for 10 minutes in the molecular beam epitaxy cavity, and then heat it to 680°C for 10 minutes.
[0099] (3) A 50 nm silicon buffer layer was epitaxially grown on the heat-treated silicon substrate using molecular beam epitaxy (MBE) at a growth rate of [missing information]. The growth temperature is 400℃, then the temperature is lowered to 300℃ for annealing for 5 minutes.
[0100] (4) A 20nm ultra-high activation doping concentration single-crystal Si was epitaxially grown on the above-mentioned silicon buffer layer using molecular beam epitaxy. 063 Ge 037 :B thin film, silicon growth rate is Germanium growth rate is The growth temperature is 300℃, and the temperature of crucible B is 2000℃.
[0101] (5) Molecular beam epitaxy is used to grow single-crystal Si with ultra-high activation doping concentration. 0.63 Ge 0.37 :B. A 1nm silicon capping layer is grown at a growth rate of [missing information]. The growth temperature is 300℃.
[0102] Depend on Figure 6 It can be seen that the activation doping concentration in Example 3 is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.63 Ge 0.37 :B The surface of the thin film sample is flat and has no three-dimensional structure.
[0103] Depend on Figure 7 It can be seen that the activation doping concentration in Example 3 is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.63 Ge 0.37 :B Thin film has an ordered lattice arrangement, which is a good single crystal structure.
[0104] Depend on Figure 8 It can be seen that the activation doping concentration in Example 3 is 2.7 × 10⁻⁶. 21 cm -3 single crystal Si 0.63 Ge 0.37 The average germanium content of the B thin film is 37%, and the chemical distribution is relatively uniform along the depth direction.
[0105] Example 4
[0106] This embodiment illustrates that the activation doping concentration of the present invention is 1.8 × 10⁻⁶. 21 cm -3 Single-crystal Si:B thin films and their preparation methods are described. Specifically, the preparation method of single-crystal Si:B thin films includes the following steps:
[0107] (1) Immerse the silicon (100) substrate for 1 minute using a 5% hydrofluoric acid solution.
[0108] (2) Anneal the silicon (100) substrate at 400°C for 10 minutes in the molecular beam epitaxy cavity, and then heat it to 680°C for 10 minutes.
[0109] (3) A 50 nm silicon buffer layer was epitaxially grown on the heat-treated silicon substrate using molecular beam epitaxy (MBE) at a growth rate of [missing information]. The growth temperature is 400℃, then the temperature is lowered to 350℃ for annealing for 5 minutes.
[0110] (4) A 20 nm ultra-high activation doping concentration single-crystal Si:B thin film was epitaxially grown on the above-mentioned silicon buffer layer using molecular beam epitaxy (MBE) technology, with a silicon growth rate of [missing information]. The growth temperature was 350℃, the boron crucible temperature was 1950℃, and then the temperature was lowered to 300℃ for annealing for 2 minutes.
[0111] (5) A 1 nm silicon capping layer was grown on the above-mentioned ultra-high activation doping concentration single-crystal Si:B thin film using molecular beam epitaxy, at a growth rate of [missing information]. The growth temperature is 300℃.
[0112] Depend on Figure 9 It can be seen that the activation doping concentration in Example 4 is 1.8 × 10⁻⁶. 21 cm -3 The surface of the single-crystal Si:B thin film sample is flat and has no three-dimensional structure.
[0113] Example 5
[0114] This embodiment illustrates that the activation doping concentration of the present invention is 2.0 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B Thin films and their preparation methods. Specifically, single-crystal Si 0.72 Ge 0.28 The preparation method of :B thin film includes the following steps:
[0115] (1) Immerse the silicon (100) substrate for 1 minute using a 5% hydrofluoric acid solution.
[0116] (2) Anneal the silicon (100) substrate at 400°C for 10 minutes in the molecular beam epitaxy cavity, and then heat it to 680°C for 10 minutes.
[0117] (3) A 50 nm silicon buffer layer was epitaxially grown on the heat-treated silicon substrate using molecular beam epitaxy (MBE) at a growth rate of [missing information]. The growth temperature is 400℃, then the temperature is lowered to 300℃ for annealing for 5 minutes.
[0118] (4) A 20nm ultra-high activation doping concentration single-crystal Si was epitaxially grown on the above-mentioned silicon buffer layer using molecular beam epitaxy. 0.72 Ge 0.28 :B thin film, silicon growth rate is Germanium growth rate is The growth temperature was 300℃, and the boron crucible temperature was 1950℃.
[0119] (5) Molecular beam epitaxy is used to grow single-crystal Si with ultra-high activation doping concentration. 0.72 Ge 0.28A 1nm silicon capping layer is grown on a thin film at a growth rate of . The growth temperature is 300℃.
[0120] Depend on Figure 10 It can be seen that the activation doping concentration in Example 5 is 2.0 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B The surface of the thin film sample is flat and has no three-dimensional structure.
[0121] Example 6
[0122] This embodiment illustrates that the activation doping concentration of the present invention is 1.5 × 10⁻⁶. 21 cm -3 single crystal Si 0.72 Ge 0.28 :B Thin films and their preparation methods. Specifically, single-crystal Si 0.72 Ge 0.28 The preparation method of :B thin film includes the following steps:
[0123] (1) Immerse the silicon (100) substrate for 1 minute using a 5% hydrofluoric acid solution.
[0124] (2) Anneal the silicon (100) substrate at 400°C for 10 minutes in the molecular beam epitaxy cavity, and then heat it to 680°C for 10 minutes.
[0125] (3) A 50 nm silicon buffer layer was epitaxially grown on the heat-treated silicon substrate using molecular beam epitaxy (MBE) at a growth rate of [missing information]. The growth temperature is 400℃, then the temperature is lowered to 300℃ for annealing for 5 minutes.
[0126] (4) A 20nm ultra-high activation doping concentration single-crystal Si was epitaxially grown on the above-mentioned silicon buffer layer using molecular beam epitaxy. 0.72 Ge 0.28 :B thin film, silicon growth rate is Germanium growth rate is The growth temperature is 400℃, and the boron crucible temperature is 2000℃.
[0127] (5) Molecular beam epitaxy is used to grow single-crystal Si with ultra-high activation doping concentration. 0.72 Ge 0.28 A 1nm silicon capping layer is grown on a thin film at a growth rate of . The growth temperature is 300℃.
[0128] Depend on Figure 11 It can be seen that the activation doping concentration in Example 6 is 1.5 × 10⁻⁶. 21 cm -3single crystal Si 0.72 Ge 0.28 :B The surface of the thin film sample is flat and has no three-dimensional structure.
Claims
1. A Si:B single-crystal thin film with ultra-high activation doping concentration, wherein, The activation doping concentration of B is at least 1.5 × 10⁻⁶. 21 cm -3 .
2. The Si:B single crystal thin film with ultra-high activation doping concentration according to claim 1, wherein, The thickness of the Si:B single crystal thin film is 10-200 nm, preferably 10-50 nm, and more preferably 20 nm.
3. A silicon-based composite structure, comprising: silicon substrate, A silicon buffer layer located on the silicon substrate, and An ultra-high activation doping concentration Si:B single crystal thin film located on the silicon buffer layer; The activation doping concentration of B is at least 1.5 × 10⁻⁶. 21 cm -3 ; Preferably, the thickness of the Si:B single crystal thin film is 10-200 nm, more preferably 10-50 nm, and even more preferably 20 nm.
4. A method for preparing a Si:B single-crystal thin film with ultra-high activation doping concentration as described in any one of claims 1-2, comprising the following steps performed sequentially in a molecular beam epitaxy cavity: (1) Perform in-situ heat treatment on the silicon substrate; (2) A silicon buffer layer is grown on the silicon substrate after heat treatment in step (1); (3) A Si:B single crystal thin film with ultra-high activation doping concentration is epitaxially grown on the surface of the silicon buffer layer; (4) Optionally, a silicon capping layer is epitaxially grown on the Si:B single crystal thin film with ultra-high activation doping concentration; in, The epitaxial growth of a Si:B single crystal thin film with ultra-high activation doping concentration on the surface of the silicon buffer layer in step (3) is carried out under the following conditions: the temperature of the boron source thermal evaporation crucible is 1900-2050℃.
5. The method according to claim 4, wherein, The epitaxial growth of a Si:B single crystal thin film with ultra-high activation doping concentration on the surface of the silicon buffer layer in step (3) is carried out at a growth temperature of 300-600℃. Preferably, in step (3), the epitaxial growth of a Si:B single crystal thin film with ultra-high activation doping concentration on the surface of the silicon buffer layer is carried out at a silicon growth rate of [missing information]. It was carried out under the following conditions; Preferably, the in-situ heat treatment of the silicon substrate in step (1) is carried out by a method including the following steps: heating the silicon substrate to 400-550°C for annealing for 5-30 minutes, and then heating it to 600-750°C for annealing for 5-30 minutes; Preferably, the growth of the silicon buffer layer on the silicon substrate after heat treatment in step (1) in step (2) is carried out by a method including the following steps: growing the silicon buffer layer on the silicon substrate at 300-600°C using molecular beam epitaxy. Preferably, the epitaxial growth of the silicon capping layer on the ultra-high activation doping concentration Si:B single crystal thin film in step (4) is carried out under the following conditions: growth temperature of 200-350℃ and Si growth rate of...
6. A Si with ultra-high activation doping concentration 1-x Ge x :B Single crystal thin film, wherein, 0.25≤x≤0.4, the activation doping concentration of B is at least 1.5×10⁻⁶. 21 cm -3 ; Preferably, the Si 1-x Ge x The thickness of the B single crystal thin film is 10-200 nm, more preferably 10-50 nm, and even more preferably 20 nm.
7. A silicon-based composite structure, comprising: silicon substrate, A silicon buffer layer located on the silicon substrate, and The ultra-high activation doping concentration of Si located above the silicon buffer layer 1-x Ge x :B Single crystal thin film; The activation doping concentration of B is at least 1.5 × 10⁻⁶. 21 cm -3 ; Preferably, the Si 1-x Ge x The thickness of the B single crystal thin film is 10-200 nm, more preferably 10-50 nm, and even more preferably 20 nm.
8. A method for preparing Si with ultra-high activation doping concentration as described in claim 6 1-x Ge x The method for producing single-crystal thin films includes the following steps performed sequentially in a molecular beam epitaxy cavity: (1) Perform in-situ heat treatment on the silicon substrate; (2) A silicon buffer layer is grown on the silicon substrate after heat treatment in step (1); (3) Epitaxially growing Si with ultra-high activation doping concentration on the surface of the silicon buffer layer. 1-x Ge x :B Single crystal thin film; (4) Optionally, in the ultra-high activation doping concentration of Si 1-x Ge x :B. Epitaxial growth of a silicon capping layer on a single-crystal thin film; in, In step (3), an ultra-high activation doping concentration Si is epitaxially grown on the surface of the silicon buffer layer. 1-x Ge x The single-crystal thin film evaporation was carried out under the following conditions: the temperature of the boron source thermal evaporation crucible was 1900-2050℃.
9. The method according to claim 8, wherein, In step (3), an ultra-high activation doping concentration Si is epitaxially grown on the surface of the silicon buffer layer. 1-x Ge x :B Single crystal thin films are grown at a temperature of 300-600℃; Preferably, in step (3), Si with an ultra-high activation doping concentration is epitaxially grown on the surface of the silicon buffer layer. 1-x Ge x :B Single-crystal thin films are produced when silicon grows at a rate of And the growth rate of germanium is It was carried out under the following conditions; Preferably, the in-situ heat treatment of the silicon substrate in step (1) is carried out by a method including the following steps: heating the silicon substrate to 400-550°C for annealing for 5-30 minutes, and then heating it to 600-750°C for annealing for 5-30 minutes; Preferably, the growth of the silicon buffer layer on the silicon substrate after heat treatment in step (1) in step (2) is carried out by a method including the following steps: growing the silicon buffer layer on the silicon substrate at 300-600°C using molecular beam epitaxy. Preferably, in step (4), the Si with ultra-high activation doping concentration... 1-x Ge x The epitaxial growth of a silicon capping layer on a single-crystal thin film was carried out under the following conditions: growth temperature of 200-350℃, and Si growth rate of...
10. The Si:B single crystal thin film with ultra-high activation doping concentration according to any one of claims 1-2, the silicon-based composite structure according to claim 3, and the Si with ultra-high activation doping concentration according to claim 6. 1-x Ge x :B. Application of single-crystal thin films or silicon-based composite structures as described in claim 7 in silicon-based integrated circuit devices.