A composite film layer with low resistance, high light transmittance and low loss and preparation method thereof

Abstract

The present invention is a composite film layer with low resistance, high light transmittance and low loss and a preparation method thereof. The composite film layer is formed by stacking single films on a substrate. The single films are three-layer elements composed of a dielectric layer / metal layer / dielectric layer from bottom to top, a porous transition layer, and a transparent conductive layer. The composite film layer is prepared by a magnetron sputtering preparation method and a film layer post-treatment method. The film layer system is reconstructed by regulating the sandwich structure and the single-layer transparent conductive film to form a new ultra-low resistance while maintaining a high light transmittance to prepare a low-resistance and high-transmittance transparent conductive film layer. While maintaining the resistance of the original sandwich structure transparent conductive film unchanged, the light transmittance of the transparent conductive oxide film layer can be further improved, which is a new transparent conductive thin film layer system architecture.

Description

Technical Field

[0001] The invention discloses a composite film layer with low resistance, high light transmittance and low loss and a preparation method thereof, belonging to the technical field of transparent conductive films. Background Art

[0002] Transparent conductive films are widely used in advanced optoelectronic devices and their systems because of their transparency and conductivity. With the rapid development of optoelectronic devices, higher requirements are placed on the optoelectronic performance of transparent conductive films. However, light transmittance and conductivity are a pair of contradictions, and the two hinder each other. A film system that combines high light transmittance and high conductivity is the ultimate pursuit of researchers. Therefore, researchers are trying to obtain a transparent conductive film system with high light transmittance and high conductivity, and maximize the performance matching index of the two. Single-layer transparent conductive films usually require high temperature (≥350℃) and considerable thickness to achieve low resistance, which hinders its application prospects; on this basis, a dielectric layer / metal / dielectric layer composite film system has been developed with high conductivity and light transmittance at low temperatures, but its general resistance can only reach 4~5Ω / □. After that, the light transmittance drops sharply, and this structure needs to meet optical / thickness matching. Summary of the invention

[0003] The present invention is designed to address the above-mentioned prior art conditions and provides a composite film layer with low resistance, high transmittance and low loss and a preparation method thereof, with the purpose of further improving the transmittance of the transparent conductive film layer while maintaining the resistance of the original sandwich structure transparent conductive film unchanged.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] The low-resistance, high-transmittance and low-loss composite film layer provided by the technical solution of the present invention is formed by stacking single films on a substrate, and the single films are three-layer elements composed of a dielectric layer / metal layer / dielectric layer, a porous transition layer, and a transparent conductive layer from bottom to top. The porous transition layer is a porous amorphous high-transmittance film layer, which plays a role in relieving film stress. The transparent conductive layer is a film layer with high conductivity and high transmittance. The interface between the layers is modified with plasma with different charge types to enhance the interlayer interface bonding force, forming a complete cycle of low-resistance, high-transmittance transparent conductive film. The number of film layer cycles is selected according to the required transmittance and resistance requirements. The film layer is subjected to thermal annealing to reduce defects between the film layers, and finally a multi-layer transparent conductive film with low resistance, high transmittance and low loss is prepared.

[0006] The steps of preparing the composite film layer with low resistance, high light transmittance and low loss are as follows:

[0007] Step 1: clean the surface of the substrate material, which is a metal, an inorganic non-metallic material or an organic material, and then place the substrate on a sample table in a magnetron sputtering vacuum chamber, and evacuate the vacuum chamber by a vacuum pump to a pressure of 2.0×10 -4 Pa~9.9×10 -4 Pa;

[0008] Step 2: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the substrate surface, and restore the vacuum state in the vacuum chamber after cleaning;

[0009] Step 3: introduce oxygen + argon mixed gas into the vacuum chamber, apply DC pulse power to the target material for ignition, the power is 50W ~ 2000W, pre-sputter for 5min ~ 30min, start to plate a dielectric layer on the surface of the substrate material, the gas pressure in the vacuum chamber is 0.4Pa ~ 5Pa during coating, the coating time is 1min ~ 30min, then turn off the DC pulse power, and restore the vacuum in the vacuum chamber after completion;

[0010] The target material is a semiconductor oxide target material or a non-oxide target material;

[0011] Step 4: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the surface of the dielectric layer, and restore the background vacuum state after cleaning;

[0012] Step 5: introduce 50-500 sccm of argon into the vacuum chamber, apply a DC pulse power supply to the metal target, the power is 10-500 W, the gas pressure is controlled at 0.2-5 Pa, and the metal layer is deposited by pre-sputtering for 1-10 minutes. The deposition time is 1-30 minutes. After the deposition is completed, the sputtering power supply and the gas valve are turned off, and the power supply and the gas valve are turned off to quickly restore the background vacuum;

[0013] Step 6: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the metal layer surface, and restore the background vacuum state after cleaning;

[0014] Step 7: Introduce a mixed gas of oxygen and argon into the vacuum chamber, apply a DC pulse power supply to the target material, the power is 50W to 2000W, pre-sputter for 5min to 30min, and start to plate a dielectric layer on the surface of the metal layer. During the coating, the gas pressure in the vacuum chamber is 0.4Pa to 5Pa, and the coating time is 1min to 30min. Then turn off the DC pulse power supply, and restore the vacuum in the vacuum chamber after completion;

[0015] The target material is a semiconductor oxide target material or a non-oxide target material;

[0016] Step 8: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the surface of the dielectric layer, and restore the background vacuum state after cleaning;

[0017] Step 9: Introduce a mixed gas of oxygen and argon into the vacuum chamber, apply a DC pulse power supply to the target material, the power is 50W to 2000W, pre-sputter for 1min to 30min, and start to plate a porous transition layer on the surface of the dielectric layer. During the coating, the gas pressure in the vacuum chamber is 0.2Pa to 5Pa, the coating time is 1min to 30min, and then turn off the DC pulse power supply. After completion, restore the background vacuum;

[0018] The target material is a semiconductor oxide target material or a non-oxide target material;

[0019] Step 10: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the surface of the porous transition layer, and restore the background vacuum state after cleaning;

[0020] Step 11: introduce oxygen + argon mixed gas into the vacuum chamber, apply a DC pulse power supply to the target material, the power is 50W to 2000W, pre-sputter for 1min to 30min, and start to plate a transparent conductive layer on the surface of the porous transition layer. During the coating, the gas pressure in the vacuum chamber is 0.2Pa to 5Pa, the coating time is 1min to 30min, and then turn off the DC pulse power supply. After completion, restore the background vacuum;

[0021] The target material is a semiconductor oxide target material or a non-oxide target material;

[0022] Step 12: Turn off all power supplies and gas valves, and restore the background vacuum for 10 to 30 minutes, then break the air and take out the low-resistance, high-transmittance and low-loss composite film layer, and then anneal it at 80 to 200°C in vacuum or Ar / N2 / O2 for 0.5 to 3 hours to strengthen the physical properties of the composite film layer and reduce the film defect density.

[0023] The number of film layer cycles is selected according to the required transmittance and resistance requirements. The film layers are subjected to thermal annealing to reduce defects between film layers, and ultimately a multilayer transparent conductive film with low resistance, high transmittance and low loss is prepared.

[0024] In practice, the surface of the cleaned substrate material in step 1 is ultrasonically cleaned with acetone, petroleum ether and degreasing agent solution for 20 to 30 minutes, then cleaned with anhydrous ethanol for 20 to 30 minutes, and finally cleaned with deionized water for 5 to 10 minutes and then the water vapor on the surface is blown dry with clean air.

[0025] In practice, the mixing ratio of the mixed gas of argon+oxygen or argon+nitrogen in the above steps 2, 4, 6, 8 and 10 is 0% to 100%.

[0026] In practice, the mixing ratio of the mixed gas of oxygen + argon in the above steps 3, 7, 9 and 11 is 0% to 50%.

[0027] In implementation, the semiconductor oxide target material described in the above steps is ITO, IZO, AZO, or FTO.

[0028] In implementation, the non-oxide target material in the above steps is ZnS.

[0029] In implementation, the metal target material described in the above step 3 is Ag, Cu, Al, Fe, Mn, Gr, Zn, or In.

[0030] In practice, the above steps 2 to 11 are repeated 1 to 10 times to prepare a multi-layer composite film layer with low resistance, high light transmittance and low loss.

[0031] During implementation, in step five, 100 sccm of argon gas is introduced into the vacuum chamber, a DC pulse power supply is applied to the metal target with a power of 50 W and a gas pressure controlled at 0.3 Pa. The metal layer is deposited by pre-sputtering for 3 to 5 minutes and the deposition time is 1 to 3 minutes. After the deposition is completed, the sputtering power supply and the gas valve are turned off, and the power supply and the gas valve are turned off to quickly restore the background vacuum.

[0032] The technical solution of the present invention is based on the development of a transparent conductive film system with extremely low resistance (≤3Ω / □) and high transmittance (75%). By periodically stacking a single transparent conductive film layer with a dielectric layer / metal / dielectric layer and a transition layer, a low resistance and high transmittance composite system is realized. The dielectric layer / metal / dielectric layer is used as a three-layer primitive, and a porous transition layer and a transparent conductive layer are combined for optical and electrical matching. The interface conductivity enhancement, the electrical superposition effect of the metal and conductive film layers, and the optical interference matching effect are used to achieve ultra-low resistance and high transmittance matching. In addition, the stress state of the entire film system is adjusted by adjusting the thickness of the porous transition layer and the number of stacking to prevent the film from cracking and falling off.

[0033] Magnetron sputtering is a widely used thin film preparation method in industry and science, and has the advantages of high film density, excellent photoelectric properties, strong adhesion and high environmental stability. To this end, the present invention uses magnetron sputtering technology to obtain a transparent conductive film system with high light transmittance while ensuring low resistance, and further improves the photoelectric performance of the transparent conductive film system through this technical approach. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of the composite membrane layer of the present invention

[0035] Figure 2 The performance comparison of the composite film layer prepared in the embodiment of the present invention with the single layer and the multilayer transparent conductive composite film with sandwich structure is shown in FIG. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments:

[0037] See attached Figure 1 As shown, the steps for preparing the low-resistance, high-transmittance and low-loss composite film layer are as follows:

[0038] 1. Cleaning: Use alcohol, acetone, petroleum ether, degreasing agent and other chemical reagents to ultrasonically clean the glass substrate for 5 to 120 minutes, then use deionized water to clean for 5 to 30 minutes, and blow dry the remaining water vapor on the surface with clean air after taking it out. The substrate includes but is not limited to organic polymer substrates, inorganic glass substrates, and metal and non-metal substrates;

[0039] 2. Install the cleaned substrate on the sample stage and evacuate to 8.0E. -4 Later, we will prepare to plate the transparent conductive film;

[0040] 3. A mixed gas of oxygen and argon (mixing ratio of 0% to 100%) is introduced, the gas pressure is controlled at 0.05 to 5 Pa, and the substrate surface is cleaned with 300 to 2500 V plasma;

[0041] 4. Pass a mixture of oxygen and argon (mixing ratio is 0% to 50%), control the gas pressure at 0.2 to 5 Pa, use 50 to 2000 W power to sputter the oxide target, deposit for 1 to 30 minutes, and use the plasma in method 3 for bombardment strengthening. The required oxide thickness is determined according to the coating time and sputtering efficiency;

[0042] 5. A mixed gas of oxygen and argon (mixing ratio of 0% to 100%) is introduced, the gas pressure is controlled at 0.05 to 5 Pa, and the surface of the dielectric layer film is bombarded with 300 to 2500V plasma to remove suspended or weakly bonded atoms and activate the oxide surface;

[0043] 6. Quickly restore the chamber to the background vacuum, switch the metal target (Ag, Cu, Al, Fe, Mn, Gr, etc.), introduce 50-500sccm of argon, control the pressure at 0.2-5Pa, and deposit the metal layer at a power of 10-500W for 1-30min. After the deposition is completed, turn off the sputtering power supply and gas valve;

[0044] 7. Rapidly evacuate to a background vacuum below 9.0E-4 and deposit the dielectric layer in step 4;

[0045] 8. Activate the surface of the dielectric layer according to the method in step 5;

[0046] 9. Pass a mixed gas of oxygen and argon (mixing ratio is 0% to 50%), control the gas pressure at 0.2 to 5 Pa, use 50 to 2000 W power to sputter the oxide target, deposit for 1 to 30 minutes, and use the plasma in method 3 for bombardment strengthening. Determine the required oxide thickness based on the coating time and sputtering efficiency;

[0047] 10. Activate the surface of the dielectric layer according to the method in step 5;

[0048] 11. Pass a mixed gas of oxygen and argon (mixing ratio is 0% to 50%), control the gas pressure at 0.2 to 5 Pa, use 50 to 2000 W power to sputter the oxide target, deposit for 1 to 30 minutes, and use the plasma in method 3 for bombardment strengthening. Determine the required oxide thickness based on the coating time and sputtering efficiency;

[0049] 12. According to the number of repetition cycles of the multilayer film, repeat steps 1 to 8 to obtain a porous transparent conductive composite film layer.

[0050] Through the analysis of the results of the above examples, it is believed that: compared with the more widely recognized dielectric layer / metal / dielectric layer transparent conductive composite film and the film layer prepared by the sputtering method of the single-layer transparent conductive composite film, this film layer has the perfect combination of low resistance and high light transmittance that cannot be matched by the single-layer film or sandwich structure. At the same time, the magnetron sputtering multilayer film at low temperature has a lower defect density and low loss, ensuring the perfect combination of photoelectric performance. The photoelectric performance of a period of low resistance, high light transmittance and low loss film is compared with that of the single-layer and sandwich structure multilayer film, as shown in the figure. Figure 2 shown.

Claims

1. A composite film layer with low resistance, high light transmittance and low loss, characterized in that: The composite film layer is formed by stacking single films on a substrate, wherein the single films are composed of three layers of dielectric layer / metal layer / dielectric layer, a porous transition layer, and a transparent conductive layer from bottom to top; The steps of preparing the composite film layer are as follows: Step 1: clean the surface of the substrate material, which is a metal, an inorganic non-metallic material or an organic material, and then place the substrate on a sample table in a magnetron sputtering vacuum chamber, and evacuate the vacuum chamber by a vacuum pump to a pressure of 2.0×10 -4 Pa~9.9×10 -4 Pa; Step 2: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the substrate surface, and restore the vacuum state in the vacuum chamber after cleaning; Step 3: introduce oxygen + argon mixed gas into the vacuum chamber, apply DC pulse power to the target material for ignition, the power is 50W ~ 2000W, pre-sputter for 5min ~ 30min, start to plate a dielectric layer on the surface of the substrate material, the gas pressure in the vacuum chamber is 0.4Pa ~ 5Pa during coating, the coating time is 1min ~ 30min, then turn off the DC pulse power, and restore the vacuum in the vacuum chamber after completion; The target material is a semiconductor oxide target material or a non-oxide target material; Step 4: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the surface of the dielectric layer, and restore the background vacuum state after cleaning; Step 5: introduce 50-500 sccm of argon into the vacuum chamber, apply a DC pulse power supply to the metal target, the power is 10-500 W, the gas pressure is controlled at 0.2-5 Pa, and the metal layer is deposited by pre-sputtering for 1-10 minutes. The deposition time is 1-30 minutes. After the deposition is completed, the sputtering power supply and the gas valve are turned off, and the power supply and the gas valve are turned off to quickly restore the background vacuum; Step 6: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the metal layer surface, and restore the background vacuum state after cleaning; Step 7: Introduce a mixed gas of oxygen and argon into the vacuum chamber, apply a DC pulse power supply to the target material, the power is 50W to 2000W, pre-sputter for 5min to 30min, and start to plate a dielectric layer on the surface of the metal layer. During the coating, the gas pressure in the vacuum chamber is 0.4Pa to 5Pa, and the coating time is 1min to 30min. Then turn off the DC pulse power supply, and restore the vacuum in the vacuum chamber after completion; The target material is a semiconductor oxide target material or a non-oxide target material; Step 8: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the surface of the dielectric layer, and restore the background vacuum state after cleaning; Step 9: Introduce a mixed gas of oxygen and argon into the vacuum chamber, apply a DC pulse power supply to the target material, the power is 50W to 2000W, pre-sputter for 1min to 30min, and start to plate a porous transition layer on the surface of the dielectric layer. During the coating, the gas pressure in the vacuum chamber is 0.2Pa to 5Pa, the coating time is 1min to 30min, and then turn off the DC pulse power supply. After completion, restore the background vacuum; The target material is a semiconductor oxide target material or a non-oxide target material; Step 10: Introduce a mixture of argon + oxygen or argon + nitrogen into the vacuum chamber, control the pressure at 0.05-5 Pa, and use 300-2500V plasma Ar + Clean and activate the surface of the porous transition layer, and restore the background vacuum state after cleaning; Step 11: introduce oxygen + argon mixed gas into the vacuum chamber, apply a DC pulse power supply to the target material, the power is 50W to 2000W, pre-sputter for 1min to 30min, and start to plate a transparent conductive layer on the surface of the porous transition layer. During the coating, the gas pressure in the vacuum chamber is 0.2Pa to 5Pa, the coating time is 1min to 30min, and then turn off the DC pulse power supply. After completion, restore the background vacuum; The target material is a semiconductor oxide target material or a non-oxide target material; Step 12: Turn off all power supplies and gas valves, and restore the background vacuum for 10 to 30 minutes before breaking the vacuum to take out the composite film layer with low resistance, high light transmittance and low loss, and then perform vacuum or Ar / N treatment at 80 to 200 °C. 2 / O2 annealing for 0.5 to 3 hours can strengthen the physical properties of the composite film layer and reduce the defect density of the film.

2. The low-resistance, high-transmittance and low-loss composite film layer according to claim 1, characterized in that: The surface of the substrate material is cleaned in step 1 by ultrasonic cleaning with acetone, petroleum ether and degreasing agent solution for 20 to 30 minutes, then cleaning with anhydrous ethanol for 20 to 30 minutes, and finally cleaning with deionized water for 5 to 10 minutes and then blowing the surface water vapor with clean air.

3. The low-resistance, high-transmittance and low-loss composite film layer according to claim 1, characterized in that: The semiconductor oxide target materials described in the above steps are ITO, IZO, AZO, and FTO.

4. The low-resistance, high-transmittance and low-loss composite film layer according to claim 1, characterized in that: The non-oxide target material described in the above steps is ZnS.

5. The low-resistance, high-transmittance and low-loss composite film layer according to claim 1, characterized in that: The metal target materials described in the above step three are Ag, Cu, Al, Fe, Mn, Gr, Zn, and In.

6. The low-resistance, high-transmittance and low-loss composite film layer according to claim 1, characterized in that: Repeat the above steps 2 to 11 1 to 10 times to prepare a multi-layer composite film layer with low resistance, high light transmittance and low loss.

7. The low-resistance, high-transmittance and low-loss composite film layer according to claim 1, characterized in that: In step five, 100 sccm of argon is introduced into the vacuum chamber, a DC pulse power supply of 50 W is applied to the metal target, the gas pressure is controlled at 0.3 Pa, and the metal layer is deposited by pre-sputtering for 3 to 5 minutes. The deposition time is 1 to 3 minutes. After the deposition is completed, the sputtering power supply and gas valve are turned off, and the power supply and gas valve are turned off to quickly restore the background vacuum.

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