A method for preparing a hydroxyl-terminated semiconductor material

Abstract

The invention discloses a method for preparing a hydroxyl-terminated semiconductor material. The method firstly performs a hydrogenation treatment so that the semiconductor material surface has a hydrogen terminal, and then performs a hydroxylation treatment on the diamond surface by low-produced hydroxide ions through high-voltage electrolysis. The method is an efficient, clean and safe diamond surface hydroxylation method. It only needs to be performed in a plasma liquid such as deionized water without adding any chemical reagents, thereby ensuring that no impurities are introduced into the sample surface and greatly reducing the processing cost. The hydroxylation degree is higher, and the method is suitable for the preparation of high-quality hydroxyl-terminated diamond surfaces with lower defect density.

Description

Technical Field

[0001] The invention belongs to the field of microelectronic information technology materials, and in particular relates to a method for preparing a hydroxyl terminal semiconductor material. Background Art

[0002] Diamond, the "Mount Everest" of electronic materials, has ultra-wide bandgap, high carrier mobility, high breakdown field strength, extremely high thermal conductivity, as well as radiation resistance and corrosion resistance, making it very suitable for the preparation of ultra-high power and ultra-high frequency electronic devices. The diamond surface forms a diamond surface with a specific terminal structure by adsorbing other atoms or groups, and the terminal structure of the diamond surface will change the surface conductivity, affinity, work function, etc., significantly affecting the performance of electronic devices.

[0003] Hydroxyl-terminated diamond surfaces have great potential for application in the field of microelectronics. The unique charge transfer ability and stability of hydroxyl-terminated diamond surfaces have the potential for application in high-performance field effect transistor channel layers. 4 The treatment method with Fenton's reagent can appropriately increase the hydroxyl content on the diamond surface. However, the degree of surface hydroxylation is very low, and other types of oxygen-containing groups such as carbonyl, carboxyl and cyclic ether, as well as surface defects may be introduced. Traditional electrochemical anode treatment can only process heavily doped conductive diamond samples, and also faces the problem of low degree of hydroxylation. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for preparing a hydroxyl-terminated semiconductor material to solve the problem that the existing preparation method has a low degree of hydroxylation for semiconductor materials such as diamond and is prone to introduce other types of oxygen-containing groups and surface defects.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a hydroxyl-terminated semiconductor material, characterized in that it comprises the following steps:

[0007] Step 1, hydrogenating the surface of the semiconductor material by microwave plasma chemical vapor deposition to obtain a hydrogen-terminated semiconductor material;

[0008] Step 2, injecting ionizing liquid into the electrolytic cell, fixing the hydrogen-terminated semiconductor material on the metal electrode, continuously introducing nitrogen into the ionizing liquid, electrifying the metal electrode, and hydroxylating the hydrogen-terminated semiconductor material to obtain a hydroxyl-terminated semiconductor material, wherein the electrified voltage is 100 to 3000 V and the current is 0.1 to 100 mA.

[0009] A further improvement of the present invention is:

[0010] Preferably, the semiconductor material is diamond, silicon, silicon carbide or silicon nitride.

[0011] Preferably, in step 1, during the microwave plasma chemical vapor deposition process, the substrate temperature is 1000-1300° C., the hydrogen flow rate is 500 sccm, the methane flow rate is 25-50 sccm, the chamber pressure is 115-130 Torr, and the processing time is 10 min.

[0012] Preferably, in step 2, the ionizing liquid is deionized water or alcohol.

[0013] Preferably, in step 2, the alcohol is methanol, ethanol or ethylene glycol.

[0014] Preferably, in step 2, the resistivity of deionized water is 18.25 MΩ·cm.

[0015] Preferably, in step 2, the metal electrode is platinum, palladium, iridium, rhodium or gold.

[0016] Preferably, in step 2, the nitrogen flow rate is 10 to 1000 sccm.

[0017] Preferably, in step 2, the power-on time is 1 to 120 minutes.

[0018] Preferably, the temperature of the ionizing liquid is 20-80°C.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention discloses a method for preparing a hydroxyl-terminated semiconductor material. The method firstly performs a hydrogenation treatment so that the semiconductor material surface has a hydrogen terminal, and then performs a hydroxylation treatment on the diamond surface by means of a low-yield hydroxide ion produced by high-voltage electrolysis. The method is an efficient, clean and safe method for hydroxylation of the diamond surface. The method only needs to be performed in a plasma liquid such as deionized water, and no chemical reagent needs to be added, thereby ensuring that no impurities are introduced into the sample surface, and the processing cost is greatly reduced. The hydroxylation degree is higher, and the method is suitable for the preparation of high-quality hydroxyl-terminated diamond surfaces with lower defect density. The traditional anodic electrochemical oxidation treatment requires the diamond sample to be conductive, while the present preparation method has no requirements on the conductivity of the diamond, and can process intrinsic diamond samples. At the same time, the surface hydroxylation degree obtained by the traditional treatment method is low, and other types of oxygen-containing groups other than hydroxyl groups are introduced. The present preparation method can obtain a high-purity hydroxyl surface.

[0021] Furthermore, ionic liquids such as high-purity deionized water have extremely low ionization degrees, and the preparation method can effectively suppress the generation of dangerous gases such as hydrogen during electrolysis, making the treatment process safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the high-pressure electrolysis of deionized water and other liquids used in the present invention to treat diamond.

[0023] Figure 2 This is an X-ray photoelectron spectrum of the hydrogen-terminated diamond surface before the treatment of the present invention.

[0024] Figure 3 This is an X-ray photoelectron spectrum of the hydroxyl-terminated diamond surface after treatment according to the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0026] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] A method for preparing a hydroxyl-terminated semiconductor material, the method uses high-voltage electrolysis of liquids such as deionized water to achieve hydroxylation of the diamond surface, such as Figure 1 As shown, the diamond surface is hydroxylated by hydroxide ions produced by high-voltage electrolysis of deionized water. This method does not require the addition of other chemical reagents during the treatment process, and the diamond sample does not need to be doped.

[0028] The specific steps are as follows:

[0029] (1) Preparation of hydrogen termination on the surface of semiconductor materials. The surface of the semiconductor material is treated with hydrogen termination based on a microwave plasma chemical vapor deposition system to obtain a hydrogen-terminated semiconductor material; the processing conditions are: substrate temperature of 1000-1300°C, hydrogen flow rate of 500sccm, methane flow rate of 25-50sccm, chamber pressure of 115-130Torr, and processing time of 10 minutes. The semiconductor material is diamond, silicon, silicon carbide or silicon nitride.

[0030] (2) Establish a hydrogen-terminated semiconductor material processing environment. Inject ionizing liquid into the quartz electrolytic cell, fix the hydrogen-terminated semiconductor material to the metal electrode, and use 10 to 1000 sccm of nitrogen to continuously clean the deionized water to remove dissolved oxygen. The ionizing liquid is 18.25MΩcm deionized water, analytical pure methanol, ethanol or ethylene glycol and other alcohols; the material of the metal electrode is platinum, palladium, iridium, rhodium and gold and other metals that are not easily corroded by electrolysis; the ionizing liquid needs to be able to ionize to produce hydroxide ions, and the ionization degree is relatively low. If the ionization degree is too high, the voltage cannot be added, because high voltage generates high current, violent heat, and easy to burn.

[0031] (3) Hydroxylation treatment of the surface of hydrogen-terminated semiconductor materials. A direct current of 100 to 3000 V is applied to the metal electrodes, and the electrode spacing is adjusted so that the current is 0.1 to 100 mA. The diamond sample is subjected to hydroxylation treatment for 1 to 120 min, and the water temperature is maintained at 20 to 80 ° C using a constant temperature platform.

[0032] The present invention utilizes high-voltage electrolysis of liquids such as deionized water to prepare a high-quality hydroxyl-terminated diamond surface. The key points in the implementation process are:

[0033] (1) The oxygen in the air and the oxygen generated during the electrolysis process dissolve in liquids such as deionized water, which will introduce other types of oxygen-containing groups during the hydroxylation process on the diamond surface, resulting in a decrease in the hydroxyl content on the diamond surface. It is necessary to use inert gases such as nitrogen or argon to clean the liquid to ensure a low dissolved oxygen content.

[0034] (2) Voltage and current have a crucial influence on the hydroxylation process of the diamond surface. Higher voltage and current will accelerate the hydroxylation of the surface and increase the surface hydroxyl content; however, too high voltage and current will introduce a large number of defects on the surface, which will reduce the surface hydroxyl content. Therefore, it is necessary to control the appropriate voltage to 100-3000V and the appropriate current to 0.1-10mA to ensure that the diamond surface has the highest hydroxyl content and the lowest defect density.

[0035] Example 1

[0036] (1) A hydrogen-terminated diamond surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature of 1150°C, hydrogen flow rate of 500 sccm, methane flow rate of 50 sccm, chamber pressure of 125 Torr, and processing time of 10 min.

[0037] (2) Deionized water of 18.25 MΩcm was injected into a quartz electrolytic cell, the hydrogen-terminated diamond sample was fixed to a platinum anode, and 10 sccm of nitrogen was continuously introduced into the deionized water for deoxygenation.

[0038] (3) A 100 V direct current is applied to the platinum electrode, and the electrode spacing is adjusted so that the current is 0.1 mA. The diamond sample is subjected to a hydroxylation treatment for 120 min, during which the water temperature is maintained at 30° C. using a constant temperature platform.

[0039] Figure 2 This is the X-ray photoelectron spectrum of the hydrogen-terminated diamond surface. It can be seen from the figure that the main chemical bonds on the hydrogen-terminated diamond surface are CH bonds and trace amounts of sp 2 CC bond of the form; Figure 3 This is an X-ray photoelectron spectrum of the hydroxyl-terminated diamond surface after treatment according to the present invention. It can be seen from the figure that after hydroxylation treatment, C-OH bonds appear on the diamond surface and the strength of the CH bond is significantly reduced.

[0040] Example 2

[0041] (1) A hydrogen-terminated diamond surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature 1100°C, hydrogen flow rate 500 sccm, methane flow rate 25 sccm, chamber pressure 115 Torr, and processing time 10 min.

[0042] (2) Analytical-grade ethanol was injected into a quartz electrolytic cell, a hydrogen-terminated diamond sample was fixed to a palladium anode, and 100 sccm of argon was continuously introduced into the ethanol to reduce the amount of dissolved oxygen in the ethanol.

[0043] (3) A direct current of 500 V was applied to the palladium electrode, and the electrode spacing was adjusted so that the current was 1 mA. The diamond sample was subjected to a hydroxylation treatment for 40 min, during which the water temperature was maintained at 60° C. using a constant temperature platform.

[0044] Example 3

[0045] (1) A hydrogen-terminated diamond surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature 1200°C, hydrogen flow rate 500 sccm, methane flow rate 30 sccm, chamber pressure 120 Torr, and processing time 10 min.

[0046] (2) Analytical grade methanol was injected into a quartz electrolytic cell, the hydrogen-terminated diamond sample was fixed to the iridium anode, and 500 sccm of argon was continuously introduced into the methanol to reduce the amount of oxygen dissolved in the methanol.

[0047] (3) A direct current of 1000 V is applied to the iridium electrode, and the electrode spacing is adjusted so that the current is 2 mA. The diamond sample is subjected to a hydroxylation treatment for 20 min, during which the water temperature is maintained at 50° C. using a constant temperature platform.

[0048] Example 4

[0049] (1) A hydrogen-terminated diamond surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature 1300°C, hydrogen flow rate 500 sccm, methane flow rate 40 sccm, chamber pressure 130 Torr, and processing time 10 min.

[0050] (2) Analytical grade ethylene glycol was injected into a quartz electrolytic cell, a hydrogen-terminated diamond sample was fixed to a rhodium anode, and 800 sccm of nitrogen was continuously introduced into the ethylene glycol to reduce the amount of oxygen dissolved in the ethylene glycol.

[0051] (3) A direct current of 2000 V was applied to the rhodium electrode, and the electrode spacing was adjusted so that the current was 5 mA. The diamond sample was subjected to a hydroxylation treatment for 10 min, during which the water temperature was maintained at 80° C. using a constant temperature platform.

[0052] Example 5

[0053] (1) A hydrogen-terminated diamond surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature 1250°C, hydrogen flow rate 500 sccm, methane flow rate 45 sccm, chamber pressure 115 Torr, and processing time 10 min.

[0054] (2) Isopropanol was injected into a quartz electrolytic cell, a hydrogen-terminated diamond sample was fixed to a ruthenium anode, and 1000 sccm of argon was continuously introduced into the isopropanol.

[0055] (3) A 3000 V direct current is applied to the ruthenium electrode, and the electrode spacing is adjusted so that the current is 10 mA. The diamond sample is subjected to a hydroxylation treatment for 1 min, during which the water temperature is maintained at 70° C. using a constant temperature platform.

[0056] Example 6

[0057] (1) Preparation of hydrogen-terminated diamond surface. A hydrogen-terminated diamond surface was epitaxially grown based on a microwave plasma chemical vapor deposition system to obtain a hydrogen-terminated diamond sample; the growth conditions were: substrate temperature of 1050°C, hydrogen flow rate of 500 sccm, methane flow rate of 50 sccm, chamber pressure of 120 Torr, and processing time of 10 min.

[0058] (2) Establishment of diamond sample processing environment: 18.25 MΩcm deionized water was injected into the quartz electrolytic cell, the hydrogen-terminated diamond sample was fixed to the platinum anode, and 800 sccm nitrogen was used to continuously purge the deionized water to remove dissolved oxygen.

[0059] (3) Hydroxylation of diamond surface: A 1500 V direct current was applied to the platinum electrodes, and the electrode spacing was adjusted so that the current was 50 mA. The diamond sample was subjected to hydroxylation for 60 min, and the water temperature was maintained at 20-80 °C using a constant temperature platform.

[0060] Example 7

[0061] (1) A hydrogen-terminated silicon surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature of 1150°C, hydrogen flow rate of 500 sccm, methane flow rate of 50 sccm, chamber pressure of 125 Torr, and processing time of 10 min.

[0062] (2) Deionized water of 18.25 MΩcm was injected into the quartz electrolytic cell, the hydrogen-terminated silicon was fixed to the platinum anode, and 10 sccm of nitrogen was continuously introduced into the deionized water for deoxygenation.

[0063] (2) A 100 V direct current was applied to the platinum electrode, and the electrode spacing was adjusted so that the current was 0.1 mA. The silicon sample was subjected to a hydroxylation treatment for 120 min, during which the water temperature was maintained at 30° C. using a constant temperature platform.

[0064] Example 8

[0065] (1) A hydrogen-terminated silicon carbide surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature 1100°C, hydrogen flow rate 500 sccm, methane flow rate 25 sccm, chamber pressure 115 Torr, and processing time 10 min.

[0066] (2) Analytical pure ethanol was injected into a quartz electrolytic cell, a hydrogen-terminated silicon carbide sample was fixed to a palladium anode, and 100 sccm of argon was continuously introduced into the ethanol to reduce the amount of dissolved oxygen in the ethanol.

[0067] (3) A direct current of 500 V was applied to the palladium electrode, and the electrode spacing was adjusted so that the current was 1 mA. The silicon carbide sample was subjected to a hydroxylation treatment for 40 min, during which the water temperature was maintained at 60° C. using a constant temperature platform.

[0068] Example 9

[0069] (1) A hydrogen-terminated silicon nitride surface was epitaxially grown using a microwave plasma chemical vapor deposition system. The growth conditions were: substrate temperature 1200°C, hydrogen flow rate 500 sccm, methane flow rate 30 sccm, chamber pressure 120 Torr, and processing time 10 min.

[0070] (2) Analytical grade methanol was injected into a quartz electrolytic cell, a hydrogen-terminated silicon nitride sample was fixed to an iridium anode, and 500 sccm of argon was continuously introduced into the methanol to reduce the amount of oxygen dissolved in the methanol.

[0071] (3) A direct current of 1000 V is applied to the iridium electrode, and the electrode spacing is adjusted so that the current is 2 mA. The silicon nitride sample is subjected to a hydroxylation treatment for 20 min, during which the water temperature is maintained at 50° C. using a constant temperature platform.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a hydroxyl-terminated semiconductor material, characterized in that: The following steps are involved: Step 1, hydrogenating the surface of the semiconductor material by microwave plasma chemical vapor deposition to obtain a hydrogen-terminated semiconductor material; In step 1, during the microwave plasma chemical vapor deposition process, the substrate temperature is 1000-1300° C., the hydrogen flow rate is 500 sccm, the methane flow rate is 25-50 sccm, the chamber pressure is 115-130 Torr, and the processing time is 10 min; Step 2, injecting ionizing liquid into the electrolytic cell, fixing the hydrogen-terminated semiconductor material on the metal electrode, continuously introducing nitrogen into the ionizing liquid, electrifying the metal electrode, and performing hydroxylation on the hydrogen-terminated semiconductor material to obtain a hydroxyl-terminated semiconductor material, wherein the electrified voltage is 100-3000 V and the current is 0.1-100 mA; The ionizing liquid is deionized water or alcohol; The semiconductor material is diamond, silicon, silicon carbide or silicon nitride.

2. The method for preparing a hydroxyl-terminated semiconductor material according to claim 1, characterized in that: In step 2, the alcohol is methanol, ethanol or ethylene glycol.

3. The method for preparing a hydroxyl-terminated semiconductor material according to claim 1, characterized in that: In step 2, the resistivity of deionized water is 18.25 MΩ·cm.

4. The method for preparing a hydroxyl-terminated semiconductor material according to claim 1, characterized in that: In step 2, the metal electrode is platinum, palladium, iridium, rhodium or gold.

5. The method for preparing a hydroxyl-terminated semiconductor material according to claim 1, characterized in that: In step 2, the nitrogen flow rate is 10-1000 sccm.

6. The method for preparing a hydroxyl-terminated semiconductor material according to claim 1, characterized in that: In step 2, the power-on time is 1 to 120 minutes.

7. The method for preparing a hydroxyl-terminated semiconductor material according to claim 1, characterized in that: The temperature of the ionizing fluid is 20~80℃.

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