TWI505363B - Atmospheric pressure organometallic vapor deposition provides p - type silicon wafer surface passivation method - Google Patents

Description

Atmospheric pressure organometallic vapor deposition provides a method for surface passivation of p-type germanium wafers

The present invention is a method for vapor phase deposition of a p-type tantalum wafer by atmospheric pressure organometallic vapor deposition.

In recent years, solar cells have become increasingly thinner to ensure production and reduce costs. However, solar cells have become thinner and the overall efficiency is more limited by the surface recombination rate. To this end, national research teams are working on the development of solar cell related technologies to avoid a drop in conversion efficiency. Among them, reducing the surface recombination rate through the passivation process has been confirmed as an important factor to improve the conversion efficiency of the crystal germanium solar cell.

There are three kinds of passivation materials commonly used in the solar energy industry today. One is hydrogenated cerium hydride (a-SiN _x :H), which functions as a direct contact with single crystal germanium to prevent air from reacting due to excessive time. It is also commonly applied to the anti-reflective coating of p-type germanium wafer substrate solar cells, and provides a good passivation effect on the front surface (n ⁺ emitter). However, when the hydrogenated hafnium nitride film is used for passivation of the back surface of the p-type solar cell, The positive charge carried at the interface causes the semiconductor at the interface to generate an inversion layer, causing a small amount of current loss, which limits the conversion efficiency of the solar cell.

Furthermore, the cerium oxide (SiO2) film prepared by the thermal growth method provides good back surface passivation of the low-doped p-type solar cell, but has a high thermal budget and a high temperature process (~950-1100 ° C). ), this limits the passivation process of cerium oxide in other materials.

Alumina film, alumina is a material that has been proven to have good passivation effects in light and heavily doped p-type germanium wafer substrates in recent years. When the aluminum oxide film is deposited on the wafer substrate, a layer of ruthenium dioxide is formed at the interface, and a built-in negative charge exists at the interface between the cerium oxide and the alumina (Q _f = 10 ^10~12 cm ^-2 ). The closer to the surface of the substrate, the lower the concentration of a few carriers. Here we take the p-type germanium wafer substrate as an example. If a negatively charged dielectric layer is applied to the surface of the substrate, a small number of carriers close to the surface of the substrate can be used. Electron) drive away to avoid carrier recombination or defect capture, reducing surface recombination rate.

Most of the current aluminum film growth techniques are Sputter Deposition and Atom Layer Deposition (ALD). Although this technology can form high-quality aluminum film, it has a small yield. The disadvantages of complicated process and high cost.

Therefore, in view of the defects of the passivation of the above-mentioned conventional p-type germanium wafer substrate, the present applicant has researched the atmospheric pressure organic metal of the present invention by utilizing its professional vision and professional knowledge in the spirit of research innovation and excellence. A method of chemical vapor deposition to form an aluminum oxide film.

An object of the present invention is to provide a method for providing surface passivation of a p-type germanium wafer by atmospheric pressure organometallic vapor deposition, the method comprising: first cleaning a p-type germanium wafer substrate; and placing the p-type germanium wafer substrate in a reaction chamber In the body, a first mixed gas composed of hydrochloric acid and hydrogen is introduced, and the p-type germanium wafer substrate is heat-treated at 1100 to 1200 ° C; and the reaction chamber is made of oxygen, nitrogen and trimethyl aluminum. The dry mixed gas forms an aluminum oxide film on the p-type germanium wafer substrate, and the formation time is between 8 and 17 minutes, and the temperature is between 430 and 500 ° C. Finally, the reaction chamber is introduced with hydrogen gas and The p-type ruthenium wafer substrate is tempered at a temperature of 400 to 500 ° C for a second mixed gas of 1:9 ratio, and the passivated p-type ruthenium wafer substrate is completed for 5 to 30 minutes. The above dry mixed gas is composed of oxygen, nitrogen and trimethylaluminum, and its oxygen The flow rate is between 45~152 cc/min, and the flow rate of trimethylaluminum is 10 umole/min. The minority carrier lifetime of the p-type germanium wafer substrate passivated by this method reaches 1308.4 us, and the surface recombination rate is 25.796. Cm/s.

Another object of the present invention is to provide a method for providing surface passivation of a p-type germanium wafer by atmospheric pressure organometallic vapor deposition, the method comprising the steps of: first cleaning a p-type germanium wafer substrate; and placing the p-type germanium wafer substrate in a reaction Inside the cavity, a first mixed gas composed of hydrochloric acid and hydrogen is introduced, and the p-type germanium wafer substrate is heat-treated at 1100 to 1200 ° C; and the reaction chamber is passed through water, nitrogen and trimethyl a wet mixed gas composed of aluminum, forming an aluminum oxide film on the p-type germanium wafer substrate, the formation time is between 8 and 17 minutes, and the temperature is between 350 and 500 ° C; finally, the reaction chamber is introduced. The p-type ruthenium wafer substrate is tempered at 400 to 500 ° C for a second mixed gas composed of hydrogen and nitrogen in a ratio of 1:9, and the passivated p-type ruthenium wafer substrate is completed in 5 to 30 minutes. The above wet mixed gas is composed of oxygen, nitrogen and trimethylaluminum, and the water vapor flow rate is between 45 and 152 cc/min, and the trimethylaluminum flow rate is 19 umole/min, and the method is passivated. The p-type germanium wafer substrate has a minority carrier lifetime of 1915.27 us and a surface recombination rate of 17.622 cm/s.

According to the above disadvantages, the present invention provides a method for providing surface passivation of a p-type germanium wafer by atmospheric pressure organometallic vapor deposition, which can be deposited at normal pressure and low temperature, and obviously increases production safety and reduces production cost.

The present invention will be described in detail with reference to the accompanying drawings, in which The illustrations used are for the purpose of illustration and supplementary description, and are not necessarily true proportions and precise configurations after the implementation of the present invention. Therefore, the present invention should not be construed as limiting the scope and configuration of the attached drawings. The scope of rights in actual implementation is described first.

Referring to FIG. 1 , a flow chart of a method for providing surface passivation of a p-type germanium wafer by atmospheric pressure organic metal vapor deposition according to the present invention includes the following steps: Step S11: first cleaning a p-type germanium wafer substrate The p-type ruthenium wafer substrate was spun in trichloroethylene (TCE), ultrasonically oscillated for 3 minutes, the surface of the substrate was washed with oil stains, and then fluorided with acetone for 3 minutes to wash the organic matter and trichloroethylene on the substrate. Then, the substrate was placed at 75 ° C, and washed with a 20% potassium hydroxide (KOH) solution for five minutes, then vortexed with deionized water for 3 minutes, and finally the substrate was immersed in a hydrofluoric acid solution (HF: H ₂ O). 1:10) removing the oxide layer on the surface of the substrate; step S12: placing the p-type germanium wafer substrate in a reaction chamber, and introducing a first mixed gas composed of hydrochloric acid and hydrogen, at 1100 to 1200 ° C The p-type germanium wafer substrate is subjected to heat treatment; in step S13, a dry mixed gas composed of oxygen, nitrogen and trimethylaluminum is introduced into the reaction chamber, and an aluminum oxide film is formed on the p-type germanium wafer substrate to form a time medium. Between 8 and 17 minutes, the temperature is between 430 and 500 °C. The oxygen flow rate is between 45 and 152 cc/min, and the trimethyl aluminum flow rate is 10 umole/min. Step S14: Finally, the reaction chamber is composed of hydrogen and nitrogen in a ratio of 1:9. The p-type ruthenium wafer substrate is tempered at 400 to 500 ° C for the second mixed gas, and the passivated p-type ruthenium wafer substrate is completed for 5 to 30 minutes.

The p-type germanium wafer substrate passivated by the above method has a minority carrier lifetime of 1308.4 us and a surface recombination rate of 25.796 cm/s.

Referring to FIG. 2, a flow chart of a method for providing surface passivation of a p-type germanium wafer by atmospheric pressure organometallic vapor deposition according to the present invention includes the following steps: Step S21: first cleaning a p-type germanium wafer substrate The p-type ruthenium wafer substrate was spun in trichloroethylene (TCE), ultrasonically oscillated for 3 minutes, the surface of the substrate was washed with oil stains, and then fluorided with acetone for 3 minutes to wash the organic matter and trichloroethylene on the substrate. Then, the substrate was placed at 75 ° C, and washed with a 20% potassium hydroxide (KOH) solution for five minutes, then vortexed with deionized water for 3 minutes, and finally the substrate was immersed in a hydrofluoric acid solution (HF: H ₂ O). 1:10) removing the oxide layer on the surface of the substrate; step S22: placing the p-type germanium wafer substrate in a reaction chamber, and introducing a first mixed gas composed of hydrochloric acid and hydrogen, at 1100 to 1200 ° C The p-type germanium wafer substrate is subjected to heat treatment; in step S23, a wet mixed gas composed of water vapor, nitrogen gas and trimethylaluminum is introduced into the reaction chamber, and an aluminum oxide film is formed on the p-type germanium wafer substrate to form an aluminum oxide film. The time is between 8 and 17 minutes, and the temperature is between 350 and 500 °C. The flow rate of water vapor is between 45 and 152 cc/min, and the flow of trimethylaluminum is 19 umole/min. Step S24: Finally, the reaction chamber is composed of hydrogen and nitrogen in a ratio of 1:9. The second mixed gas is tempered at 400 to 500 ° C for the p-type germanium wafer substrate, and the passivated p-type germanium wafer substrate is completed in 5 to 30 minutes.

The minority carrier life cycle of the p-type germanium wafer substrate passivated by the above method is reached. 1915.27 us, surface recombination rate is 17.622 cm / s.

The above-mentioned implementation examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Any equivalent modifications or changes to the scope of this creation are not included in the spirit and scope of this creation. In the scope.

S11~S14‧‧‧Step process

S21~S24‧‧‧Step process

Figure 1 is a flow chart of the method of the present invention.

Figure 2 is a flow chart of the method of the present invention.

S11~S14‧‧‧Step process

Claims (10)

An atmospheric pressure organometallic vapor deposition method for providing passivation of a p-type germanium wafer surface comprises the steps of: cleaning a p-type germanium wafer substrate; and introducing a first mixed gas composed of hydrochloric acid and hydrogen into a reaction chamber to 1100~ The p-type germanium wafer substrate is heat-treated at 1200 ° C; a dry mixed gas composed of oxygen, nitrogen and trimethyl aluminum is introduced into the reaction chamber, and an aluminum oxide film is formed on the p-type germanium wafer substrate to form a time medium. Between 8 and 17 minutes; a second mixed gas composed of hydrogen and nitrogen is introduced into the reaction chamber, and the p-type germanium wafer substrate is tempered at 400 to 500 ° C for 5 to 30 minutes to complete passivation. P-type germanium wafer substrate. The atmospheric pressure organometallic vapor deposition as described in claim 1 provides a method for surface passivation of a p-type germanium wafer, wherein the dry mixed gas is composed of oxygen, nitrogen and trimethylaluminum, and the oxygen flowmeter is interposed. Between 45 and 152 cc/min, the flow of trimethylaluminum is 10 umole/min. The atmospheric pressure organometallic vapor deposition as described in claim 1 provides a method for surface passivation of a p-type germanium wafer, wherein the p-type germanium wafer substrate forms an aluminum oxide film at a temperature between 430 and 500 °C. The atmospheric pressure organometallic vapor deposition as described in claim 1 provides a method for surface passivation of a p-type germanium wafer, wherein the second mixed gas is composed of hydrogen and nitrogen. The mixing ratio of hydrogen to nitrogen is 1:9. The atmospheric pressure organometallic vapor deposition as described in claim 1 provides a method for surface passivation of a p-type germanium wafer, wherein the passivated p-type germanium wafer substrate has a minority carrier lifetime of 1308.4 us, and the surface recombination rate is 25.796 cm/s. An atmospheric pressure organometallic vapor deposition method for providing passivation of a p-type germanium wafer surface comprises the steps of: cleaning a p-type germanium wafer substrate; and introducing a first mixed gas composed of hydrochloric acid and hydrogen into a reaction chamber to 1100~ The p-type germanium wafer substrate is heat-treated at 1200 ° C; and a wet mixed gas composed of water vapor, nitrogen gas and trimethyl aluminum is introduced into the reaction chamber, and an aluminum oxide film is formed on the p-type germanium wafer substrate to form an aluminum oxide film. The time is between 8 and 17 minutes; a second mixed gas composed of hydrogen and nitrogen is introduced into the reaction chamber, and the p-type germanium wafer substrate is tempered at 400 to 500 ° C for 5 to 30 minutes. The passivated p-type germanium wafer substrate is completed. The atmospheric pressure organometallic vapor deposition as described in claim 6 provides a method for surface passivation of a p-type germanium wafer, wherein the wet mixed gas is composed of water vapor, nitrogen gas and trimethyl aluminum. Between 45 and 152 cc/min, the trimethylaluminum is 19 umole/min. The atmospheric pressure organometallic vapor deposition as described in claim 6 provides a method for surface passivation of a p-type germanium wafer, wherein the p-type germanium wafer substrate forms an aluminum oxide film at a temperature between 350 and 500 °C. The atmospheric pressure organometallic vapor deposition as described in claim 6 provides a method for surface passivation of a p-type germanium wafer, wherein the second mixed gas is composed of hydrogen and nitrogen, and the mixing ratio of the hydrogen to the nitrogen is 1: 9. The atmospheric pressure organometallic vapor deposition as described in claim 6 provides a method for surface passivation of a p-type germanium wafer, wherein the passivated p-type germanium wafer substrate has a minority carrier lifetime of 1915.27 us, and the surface recombination rate is 17.622 cm/s.