Indium phosphide surface etching and passivation dual-function etching solution
By using a dual-function etching solution composed of benzenesulfonic acid, hydrogen peroxide, and a solvent, the problems of poor etching selectivity and secondary oxidation of InP surface residues and oxide layers were solved, achieving efficient etching and passivation integration, and improving the electrical performance and reliability of InP devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTH WEST INST OF TECHN PHYSICS
- Filing Date
- 2025-12-24
- Publication Date
- 2026-05-08
AI Technical Summary
In the prior art, the etching selectivity of InP surface residues and oxide layers is poor, resulting in a rough surface that is prone to over-etching. Furthermore, without passivation treatment, secondary oxidation is likely to occur, affecting device performance and reliability.
A dual-function etching solution composed of benzenesulfonic acid or its derivatives, hydrogen peroxide and solvent is used to remove InP surface residues and form a passivation layer through chemical reaction, achieving integrated etching and passivation.
It achieves efficient removal of residues and oxide layers from InP surfaces, improving surface quality, reducing production costs, reducing processes, and ensuring that the chemical composition is safe and easily degradable.
Smart Images
Figure CN121991693A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor manufacturing technology and relates to a dual-function etching solution for indium phosphide surface etching and passivation, which is used to improve the electrical performance and reliability of InP devices. Background Technology
[0002] Solid-state diffusion is an essential process in InP device fabrication. This process utilizes a solid compound (such as Zn3P2) as a dopant source, which decomposes at high temperatures to release dopant atoms, allowing them to diffuse into the InP lattice and form doped regions. However, solid-state diffusion can leave dopant compounds on the InP surface, leading to surface roughness or leakage channels. Furthermore, InP is prone to forming unstable oxide layers (such as InO) when exposed to air. x InPO x (etc.), increasing the interface state density. Therefore, the etching process for InP surface residues and oxide layers, and the passivation process for InP surface, are of great significance for improving the performance and reliability of InP devices.
[0003] In conventional InP etching and passivation processes, conventional etching solutions (such as hydrochloric acid (HCl), sulfuric acid (H2SO4), and liquid bromine (Br2)) are typically used to etch away surface residues and oxide layers on InP, followed by passivation of the exposed InP surface. This etching and passivation process suffers from the following technical problems: ① Conventional etching solutions have poor selectivity for InP and its surface residues or oxide layers, easily causing over-etching and resulting in surface pits; ② The surface is relatively rough after etching with conventional solutions; ③ After conventional etching, the InP surface is not passivated, making it susceptible to secondary oxidation. These problems lead to InP surface degradation, resulting in increased scattering loss and decreased electrical performance of the device. Therefore, there is an urgent need to develop a novel etching solution that can balance the efficiency of InP surface residue removal, surface quality, and surface passivation capability. Summary of the Invention
[0004] (a) Purpose of the invention The purpose of this invention is to provide a dual-function etching solution for InP surface etching and passivation. By optimizing the etching solution formulation, the problems of InP surface residue and secondary oxidation are solved, thereby improving device reliability.
[0005] (II) Technical Solution To address the aforementioned technical problems, this invention provides a dual-function etching solution for InP surface etching and passivation, which is formulated from benzenesulfonic acid or its derivatives, an oxidant, and a solvent.
[0006] Furthermore, the general structural formula of the benzenesulfonic acid or its derivatives is as follows: Among them, R1, R2, R4, and R5 groups are independently selected from hydrogen and fluorine atoms, respectively; R3 group is selected from H atoms, F atoms, C1~C1 atoms. 12 Straight-chain alkyl or C1~C 12 One of the straight-chain perfluoroalkyl groups.
[0007] Furthermore, the oxidant is hydrogen peroxide.
[0008] Furthermore, the solvent is one or more of ethanol, isopropanol, acetone, tetrahydrofuran, or acetonitrile.
[0009] Furthermore, the mixing ratio of benzenesulfonic acid or its derivatives, the oxidant, and the solvent is as follows: the oxidant and solvent form a solution A with a volume ratio of 1:2 to 10; benzenesulfonic acid or its derivatives form a solution B with a concentration of 1 to 6 mol / L; and solutions A and B are mixed at a volume ratio of 1:1. This invention also provides a method for preparing a dual-function etching solution for InP surface etching and passivation, which includes the following steps: Step 1: Mix a set amount of solvent and a set amount of oxidant to obtain solution A. In solution A, the volume ratio of oxidant to solvent is 1:2~10. Step 2: Take a set amount of solvent and a set amount of benzenesulfonic acid or its derivative and mix them to obtain solution B. The concentration of benzenesulfonic acid or its derivative in solution B is 1 ~ 6 mol / L. Step 3: Mix solution A and solution B at a volume ratio of 1:1 to obtain a dual-function etching solution for InP surface etching and passivation.
[0010] Further, in step one: take a set amount of solvent into a brown reagent bottle, then slowly add a set amount of oxidant into the brown reagent bottle, stir at room temperature in the dark for 60 minutes to obtain solution A.
[0011] Further, in step two: take a set amount of the solvent into a reagent bottle, and then slowly add a set amount of benzenesulfonic acid or its derivative into the reagent bottle, stir at room temperature for 60 minutes until the benzenesulfonic acid or its derivative is completely dissolved to obtain solution B.
[0012] Further, in step three: solution A and solution B are mixed at a volume ratio of 1:1 and stirred at room temperature in the dark for 30 minutes to obtain the dual-function etching solution for InP surface etching and passivation.
[0013] Further, 50 mL of ethanol was placed in a brown reagent bottle, and 10 mL of H2O2 was slowly added dropwise to the brown reagent bottle. The mixture was stirred at room temperature in the dark for 60 minutes to obtain an H2O2 ethanol solution. 50 mL of ethanol was placed in a reagent bottle, and 23.7 g of benzenesulfonic acid was weighed and slowly added to the ethanol. The mixture was stirred at room temperature for 60 minutes until the benzenesulfonic acid was completely dissolved to obtain an ethanol solution of benzenesulfonic acid. The ethanol solution of benzenesulfonic acid was slowly added to the brown reagent bottle containing the H2O2 ethanol solution. The mixture was stirred at room temperature in the dark for 30 minutes to ensure uniform mixing, thus obtaining a dual-function etching and passivation etching solution.
[0014] (III) Beneficial Effects The dual-function etching solution for indium phosphide surface etching and passivation provided by the above technical solution has the following beneficial effects: (1) The dual-function etching solution can simultaneously complete the etching and passivation of InP in a single-step process, realizing the integrated etching-passivation, effectively reducing the number of steps (the traditional process requires at least two steps) and reducing production costs.
[0015] (2) The dual-function etching solution causes less damage to the InP surface and has a lower surface roughness after etching, which can meet the processing requirements of high-precision devices.
[0016] (3) The chemical components involved in the dual-function etching solution have low biotoxicity and are easily degraded, and can replace traditional highly toxic etching solutions (such as Br2, HF, etc.).
[0017] (4) Dual-function etching solution has the characteristics of simple composition, simple preparation method and low cost. Attached Figure Description
[0018] Figure 1 (a) is a SEM image of the InP surface after etching with conventional sulfuric acid etching solution, and (b) is a SEM image of the InP surface after etching with the dual-function etching solution provided by the present invention.
[0019] Figure 2 XPS P 2p spectra of InP wafer surfaces treated with the dual-functional etchant provided by this invention, treated with conventional sulfuric acid etchant, and untreated are shown respectively. Detailed Implementation
[0020] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.
[0021] In this embodiment, the dual-function etching solution for InP surface etching and passivation is prepared by benzenesulfonic acid or its derivatives, oxidant and solvent.
[0022] The general structural formula of the benzenesulfonic acid or its derivatives is as follows: The R1, R2, R4, and R5 groups can be independently selected from hydrogen (H) and fluorine (F) atoms, respectively; the R3 group can be selected from H atoms, F atoms, C1~C1 atoms. 12 Straight-chain alkyl or C1~C 12 Straight-chain perfluoroalkyl groups.
[0023] The oxidant is hydrogen peroxide (H2O2).
[0024] The solvent is one or more of ethanol, isopropanol, acetone, tetrahydrofuran, or acetonitrile.
[0025] The specific steps for preparing the dual-function etching solution for InP surface etching and passivation in this embodiment are as follows: Step 1: Take a predetermined amount of solvent into a brown reagent bottle, then slowly add a predetermined amount of oxidant to the brown reagent bottle, and stir for 60 minutes at room temperature in the dark to obtain solution A. In solution A, the volume ratio of the oxidant to the solvent is 1:2~10.
[0026] Step 2: Take the predetermined amount of the solvent into a reagent bottle, then slowly add the predetermined amount of benzenesulfonic acid or its derivative into the reagent bottle. Stir at room temperature for 60 minutes until the benzenesulfonic acid or its derivative is completely dissolved to obtain solution B. The concentration of benzenesulfonic acid or its derivative in solution B is 1~6 mol / L.
[0027] Step 3: Mix solution A and solution B at a volume ratio of 1:1 and stir at room temperature in the dark for 30 minutes to obtain the dual-function etching solution for InP surface etching and passivation.
[0028] The dual-function etchant in this embodiment has both etching and passivation effects on the surface of InP wafers. Its mechanism of action is as follows: (1) Etching effect: The benzenesulfonic acid or its derivatives have strong acidity comparable to sulfuric acid and can provide hydrogen ions (H+). + It reacts chemically with InP surface residues and oxide layers to produce soluble salts and water, etc. The specific chemical reaction equations are as follows: H2O2, as a strong oxidant, can accelerate the oxidation of InP surface residues, making them easier to remove; simultaneously, the addition of the oxidant can oxidize low-valence P. 3- Oxidized to phosphorus oxides (such as PO4) 3- (etc.), thereby effectively inhibiting the production of toxic PH3 gas. The specific chemical reaction equation is as follows: As an organic solvent, the solvent can regulate the degree of ionization of benzenesulfonic acid or its derivatives in solution by changing the solvent polarity, thereby adjusting the etching ability of the bifunctional etching solution.
[0029] (2) Passivation effect: The benzenesulfonic acid or its derivatives have polar anions that can be adsorbed onto the InP surface through electrostatic and hydrophilic / hydrophobic interactions to form a dense organic-inorganic composite layer (In-OS bonds, as shown in the figure below), thereby blocking water and oxygen permeation.
[0030] The benzenesulfonic acid or its derivatives are amphiphilic molecules capable of complexing free impurity ions (such as Zn). 2+ In 3+ (etc.), to prevent redeposition and thus improve the surface smoothness of InP.
[0031] Example 1: The surface treatment steps for InP wafers based on a dual-functional etching and passivation solution for indium phosphide are as follows: (1) Take 50 mL of ethanol into a brown reagent bottle, and then slowly add 10 mL of H2O2 into the brown reagent bottle. Stir at room temperature in the dark for 60 minutes to obtain H2O2 ethanol solution.
[0032] (2) Take 50 mL of ethanol into a reagent bottle, weigh 23.7 g of benzenesulfonic acid and slowly add it into the ethanol. Stir at room temperature for 60 minutes until the benzenesulfonic acid is completely dissolved to obtain an ethanol solution of benzenesulfonic acid.
[0033] (3) Slowly add the ethanol solution of benzenesulfonic acid to a brown reagent bottle containing H2O2 ethanol solution, stir at room temperature in the dark for 30 minutes to mix it evenly, and obtain a dual-function etching solution for etching and passivation.
[0034] (4) Add an appropriate amount of bifunctional etching solution to the culture dish, completely immerse the InP wafer to be etched in the bifunctional etching solution, etch for 5 minutes at room temperature, and then remove the InP wafer. During the etching process, continuously shake the culture dish to ensure that the surface etching reaction is fully carried out.
[0035] (5) Rinse the surface of the InP wafer with acetone, ethanol and isopropanol respectively; then put the InP wafer into a vacuum oven and bake at 85°C for 30 minutes.
[0036] Performance characterization: To more intuitively demonstrate the etching and passivation effects of the dual-function etching solution described in this invention, a conventional sulfuric acid etching solution was used for comparison. The conventional sulfuric acid etching solution has a ratio of H2SO4:H2O2:H2O = 1:1:10.
[0037] (1) The surface morphology of InP after removing the Zn3P2 solid diffusion source using conventional sulfuric acid etching solution and the aforementioned bifunctional etching solution was studied using scanning electron microscopy. For example... Figure 1 As shown in (a), after etching with conventional sulfuric acid etching solution, the InP surface is relatively rough with many etching pits, resulting in poor etching effect. However, after etching with the dual-function etching solution (as shown in [a]), the surface of InP is relatively rough with many etching pits, and the etching effect is poor. Figure 1 (b) shows that the InP surface is relatively smooth, with no etching pits. This indicates that the InP wafer etched by the dual-function etchant has higher surface quality.
[0038] (2) The binding energy of phosphorus (P) on the surface of InP wafers treated with the aforementioned bifunctional etchant, treated with conventional sulfuric acid etchant, and untreated wafers was studied using X-ray photoelectron spectroscopy (XPS). Figure 2 As shown in the figure, the P 2p spectrum reveals that after the InP wafer treated with the bifunctional etchant was left in air for 10 days, (PO4) 3- / (P2O7) 4- The characteristic peaks account for only 3.8% of the P 2p spectrum; while under the same conditions, the InP wafer surfaces treated with conventional sulfuric acid etching solution and untreated InP wafers (PO4) showed significantly higher peaks. 3- / (P2O7) 4- The characteristic peaks accounted for 19.6% and 17.0% of the P 2p spectrum, respectively. This indicates that the InP surface treated with the dual-function etching solution can effectively delay the damage caused by water, oxygen and other components in the environment, and play a role in surface passivation.
[0039] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A dual-function etching solution for InP surface etching and passivation, characterized in that, It is prepared from benzenesulfonic acid or its derivatives, an oxidizing agent and a solvent.
2. The dual-function etching solution for InP surface etching and passivation as described in claim 1, characterized in that, The general structural formula of the benzenesulfonic acid or its derivatives is as follows: Among them, R1, R2, R4, and R5 groups are independently selected from hydrogen and fluorine atoms, respectively; R3 group is selected from H atoms, F atoms, C1 ~ C atoms. 12 Straight-chain alkyl or C1 ~ C 12 One of the straight-chain perfluoroalkyl groups.
3. The dual-function etching solution for InP surface etching and passivation as described in claim 2, characterized in that, The oxidant is hydrogen peroxide.
4. The dual-function etching solution for InP surface etching and passivation as described in claim 3, characterized in that, The solvent is one or more of ethanol, isopropanol, acetone, tetrahydrofuran, or acetonitrile.
5. The dual-function etching solution for InP surface etching and passivation as described in claim 4, characterized in that, The preparation ratio of benzenesulfonic acid or its derivatives, oxidant and solvent is as follows: the oxidant and solvent form a solution A with a volume ratio of 1:2 to 10, the benzenesulfonic acid or its derivatives and the solvent form a solution B with a concentration of 1 to 6 mol / L, and the solution A and the solution B are mixed at a volume ratio of 1:
1.
6. A method for preparing a dual-function etching solution for InP surface etching and passivation as described in claim 5, characterized in that, Includes the following steps: Step 1: Mix a set amount of solvent and a set amount of oxidant to obtain solution A. In solution A, the volume ratio of oxidant to solvent is 1:2~10. Step 2: Take a set amount of solvent and a set amount of benzenesulfonic acid or its derivative and mix them to obtain solution B. The concentration of benzenesulfonic acid or its derivative in solution B is 1 ~ 6 mol / L. Step 3: Mix solution A and solution B at a volume ratio of 1:1 to obtain a dual-function etching solution for InP surface etching and passivation.
7. The method for preparing a dual-function etching solution for InP surface etching and passivation as described in claim 6, characterized in that, In step one: take a set amount of solvent into a brown reagent bottle, then slowly add a set amount of oxidant into the brown reagent bottle, stir for 60 minutes at room temperature in the dark, and obtain solution A.
8. The method for preparing a dual-function etching solution for InP surface etching and passivation as described in claim 7, characterized in that, In step two: take the set amount of the solvent into a reagent bottle, and then slowly add the set amount of benzenesulfonic acid or its derivative into the reagent bottle. Stir at room temperature for 60 minutes until the benzenesulfonic acid or its derivative is completely dissolved to obtain solution B.
9. The method for preparing a dual-function etching solution for InP surface etching and passivation as described in claim 8, characterized in that, In step three: solution A and solution B are mixed at a volume ratio of 1:1 and stirred at room temperature in the dark for 30 minutes to obtain the dual-function etching solution for InP surface etching and passivation.
10. The method for preparing a dual-function etching solution for InP surface etching and passivation as described in claim 9, characterized in that, Take 50 mL of ethanol into a brown reagent bottle, then slowly add 10 mL of H2O2 dropwise into the brown reagent bottle. Stir at room temperature in the dark for 60 minutes to obtain an H2O2 ethanol solution. Take 50 mL of ethanol into a reagent bottle, weigh 23.7 g of benzenesulfonic acid and slowly add it into the ethanol. Stir at room temperature for 60 minutes until the benzenesulfonic acid is completely dissolved to obtain an ethanol solution of benzenesulfonic acid. Slowly add the ethanol solution of benzenesulfonic acid into the brown reagent bottle containing the H2O2 ethanol solution. Stir at room temperature in the dark for 30 minutes to mix it evenly to obtain a dual-function etching and passivation etching solution.