Phosphorus-antimony co-doped silicon single crystal rod, preparation method and application

Abstract

The invention discloses a phosphorus-antimony co-doped monocrystalline silicon rod, a preparation method and application, in the phosphorus-antimony co-doped monocrystalline silicon rod, the antimony element concentration is 2.3 * 10 < 16 > atoms / cm < 3 >-1.17 * 10 < 14 > atoms / cm < 3 >, and the phosphorus element concentration is 7.66 * 10 < 15 > atoms / cm < 3 >-3.9 * 10 < 13 > atoms / cm < 3 >. According to the embodiment of the invention, the silicon single crystal rod is doped with the phosphorus element and the antimony element at the same time, and when only the phosphorus element is doped in the silicon single crystal rod, the resistivity of the obtained silicon single crystal rod is usually high at the head and low at the tail; when only the antimony element is doped in the single crystal silicon rod, due to the fact that antimony is extremely volatile, the controllability of antimony doping in the preparation process is relatively low, and the resistivity is prone to occurrence of the conditions that the head is low and the tail is high, and therefore the difference of the resistivity of the single crystal silicon rod can be reduced through co-doping of phosphorus and antimony in the implementation mode of the application.

Description

Technical Field

[0001] The invention relates to the field of solar photovoltaic technology, and in particular to a phosphorus-antimony co-doped single crystal silicon rod, a preparation method and an application thereof. Background Art

[0002] The resistivity of single crystal silicon rods has a critical influence on the resistivity of silicon wafers. However, in the process of preparing single crystal silicon rods by the direct pulling method, the resistivity of different single crystal silicon rods and even different positions of the same single crystal silicon rod will be different. The single crystal silicon rod has a large resistance variance, which leads to large differences in the resistivity of silicon wafers prepared from single crystal silicon rods. This will directly affect the performance of semiconductor devices and photovoltaic modules, and may lead to a decline in the yield and quality of silicon wafers prepared therefrom and downstream products.

[0003] Patent CN202010723937.7 discloses a method for controlling the resistivity of an n-type single crystal. It uses the difference in the segregation coefficient of phosphorus gallium to increase the resistivity of the tail of the n-type single crystal, narrowing and compressing the resistivity range to the required state. At the same time, the method adds dopants such as gallium and phosphorus silicon alloy at one time, without causing crystal growth disturbances or destroying crystal growth. However, the overall resistivity of the single crystal silicon rod prepared by it is distributed between 1 and 2Ω·cm, and the resistivity deviation between the head and the tail is still large. The yield of the silicon wafer prepared by it is still low when used in battery preparation.

[0004] In view of this, a single crystal silicon rod or a preparation method with small resistivity variance and high controllability is of great significance. Summary of the invention

[0005] The purpose of the present invention is to provide a phosphorus-antimony co-doped single crystal silicon rod, a preparation method and an application, which are beneficial to improving the resistivity hit of the single crystal silicon rod and can reduce the difference in resistance between the head and tail of the single crystal silicon rod.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a phosphorus-antimony co-doped single crystal silicon rod, wherein the antimony element concentration in the single crystal silicon rod is 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , the phosphorus concentration is 7.66×10 15 atoms / cm 3 ~3.9×10 13 atoms / cm 3 The resistivity difference between the head and tail of the single crystal silicon rod is less than 0.08Ω.cm.

[0008] In an optional embodiment, the antimony concentration in the single crystal silicon rod is 2.3×10 16atoms / cm 3 ~2.07×10 14 atoms / cm 3 , the phosphorus concentration is 2.6×10 15 atoms / cm 3 ~6.92×10 13 atoms / cm 3 ;

[0009] Preferably, the antimony concentration in the single crystal silicon rod is 5.37×10 15 atoms / cm 3 ~2.55×10 15 atoms / cm 3 , the phosphorus concentration is 1.79×10 15 atoms / cm3~8.5×10 14 atoms / cm 3 .

[0010] In an optional embodiment, the resistivity of the single crystal silicon rod is 0.2 Ω.cm to 28 Ω.cm, preferably 0.5 Ω.cm to 1.7 Ω.cm, and more preferably 0.7 Ω.cm to 1.4 Ω.cm.

[0011] In a second aspect, the present invention provides a method for preparing the phosphorus-antimony co-doped single crystal silicon rod according to any one of the aforementioned embodiments by a Czochralski method, comprising:

[0012] Silicon, phosphorus and antimony are added to the furnace after the previous single crystal silicon rod is processed.

[0013] Phosphorus addition mass M 1P =M 2p -M 3P , where M 2p M is the mass of phosphorus element required to prepare the single crystal silicon rod, in g; 3P is the mass of the remaining phosphorus in the furnace, in g;

[0014] The added mass of antimony element is M 1Sb =M 2Sb +(t2+3)×b Sb -M 3Sb , where M 2Sb M is the mass of antimony element required to prepare the single crystal silicon rod, in g; 3Sb is the mass of the remaining antimony element in the furnace, in g; b Sb is the volatility coefficient of antimony element, b SbIt is 0.1h / g~15h / g; t2 is the interval time between T3 and T4, in h; T3 is the time when the previous single crystal silicon rod is removed after the wire is broken, and T4 is the time when the barrel is removed after the last barrel of silicon material is added.

[0015] In an optional embodiment, the M 2p and M 2Sb It is calculated based on the resistivity of the single crystal silicon rod to be prepared, 3P and M 3Sb It is calculated based on the doping concentration at the tail of the previous single crystal silicon rod.

[0016] In an optional embodiment, the antimony element is added into the furnace before the seed crystal is fused and after the silicon and phosphorus are added.

[0017] In an optional embodiment, when the crystal pulling wire breaks, the furnace is temperature-adjusted and released 1 to 3 times to compensate for the doped antimony element. The mass of the compensatory doped antimony element each time is M0 = (t1+3)×a, wherein a is the temperature adjustment volatility coefficient of the antimony element, and a is 0.1h / g to 15h / g; t1 is the interval time between T1 and T2, in units of h; wherein T1 is the start time of welding, and T2 is the time when the crystal pulling wire breaks.

[0018] In an optional embodiment, the compensatory doping of antimony element is performed by using a supplementary doping device, the supplementary doping device comprises a sleeve and a push rod capable of moving along the inner cavity of the sleeve, one end of the push rod passes through the sleeve and is provided with a hopper;

[0019] The sleeve is provided with a guide groove, which includes a push-pull groove arranged along the axial direction of the push rod and a steering groove arranged along the circumference of the push rod. A sliding block capable of sliding along the guide groove is fixed to one side of the push rod located in the sleeve.

[0020] In a third aspect, the present invention provides a silicon wafer prepared from the phosphorus-antimony co-doped single crystal silicon rod described in the above embodiment, with a resistivity of 0.2Ω.cm to 28Ω.cm and an antimony concentration of 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , the phosphorus concentration is 7.66×10 15 atoms / cm 3 ~3.9×10 13 atoms / cm 3 .

[0021] In a fourth aspect, the present invention provides a battery comprising the silicon wafer described in the aforementioned embodiment.

[0022] The present invention has the following beneficial effects:

[0023] The single crystal silicon rod in the implementation manner of the present application is doped with both phosphorus and antimony. When the single crystal silicon rod is doped with only phosphorus, the resistivity of the obtained single crystal silicon rod will usually be higher at the head and lower at the tail, which will lead to a large difference in resistivity between the head and the tail of the same single crystal silicon rod. When the single crystal silicon rod is doped with only antimony, since antimony is extremely volatile, on the one hand, the controllability of antimony doping in the preparation process is relatively low, and on the other hand, the resistivity of the prepared single crystal silicon rod is prone to be lower at the head and higher at the tail. Therefore, in the implementation manner of the present application, co-doping with phosphorus and antimony is beneficial to reducing the difference in resistivity of the single crystal silicon rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic diagram of the structure of the supplementary doping device from one perspective;

[0026] Figure 2 This is a schematic structural diagram of the supplementary doping device from another perspective.

[0027] Illustration: 100-sleeve; 200-push rod; 300-hopper; 410-push-pull groove; 420-turning groove; 700-slider. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0029] The embodiment of the present invention provides a phosphorus-antimony co-doped single crystal silicon rod, wherein the antimony element concentration in the single crystal silicon rod is 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , the phosphorus concentration is 7.66×10 15 atoms / cm 3 ~3.9×10 13 atoms / cm 3 The resistivity difference between the head and tail of the single crystal silicon rod is less than 0.08Ω.cm.

[0030] The single crystal silicon rod in the embodiment of the present application is doped with both phosphorus and antimony. When only phosphorus is doped in the single crystal silicon rod, the resistivity of the obtained single crystal silicon rod is usually higher at the head and lower at the tail, which leads to a large difference in resistivity between the head and the tail of the same single crystal silicon rod. When only antimony is doped in the single crystal silicon rod, antimony is very volatile, which leads to relatively low controllability of antimony doping during the preparation process, and on the other hand, the resistivity of the prepared single crystal silicon rod is prone to be lower at the head and higher at the tail. Therefore, in the embodiment of the present application, phosphorus and antimony are co-doped, which is conducive to reducing the difference in resistivity between the head and the tail of the single crystal silicon rod. When the antimony concentration in the single crystal silicon rod is 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , the phosphorus concentration is 7.66×10 15 atoms / cm 3 ~3.9×10 13 atoms / cm 3 When the resistivity of the single crystal silicon rod is 0.2Ω.cm~28Ω.cm, the resistivity difference between the head and tail of the single crystal silicon rod co-doped with phosphorus and antimony can be controlled within 0.08Ω.cm. Compared with gallium and phosphorus co-doping, the resistivity distribution of the single crystal silicon rod is narrower, which is more conducive to improving the yield of the battery prepared therefrom.

[0031] In some embodiments, the antimony concentration in the single crystal silicon rod is 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , specifically 2.3×10 16 atoms / cm 3 , 2.0×10 16 atoms / cm 3 , 1.5×10 16 atoms / cm 3 , 1.3×10 16 atoms / cm 3 , 1.0×10 16 atoms / cm 3 ,7×10 15 atoms / cm 3 , 3×10 15 atoms / cm 3 , 1×10 15 atoms / cm 3 ,7×10 14 atoms / cm3 , 3×10 14 atoms / cm 3 , 1.17×10 14 atoms / cm 3 .

[0032] In some embodiments, the phosphorus concentration in the single crystal silicon rod is 7.66×10 15 atoms / cm 3 ~3.9×10 13 atoms / cm 3 , specifically 7.66×10 15 atoms / cm 3 5.0×10 15 atoms / cm 3 , 1.0×10 15 atoms / cm 3 , 0.7×10 15 atoms / cm 3 , 0.3×10 15 atoms / cm 3 , 0.1×10 15 atoms / cm 3 , 8×10 13 atoms / cm 3 , 5×10 13 atoms / cm 3 , 3.9×10 13 atoms / cm 3 .

[0033] In an optional embodiment, the antimony concentration in the single crystal silicon rod is 2.3×10 16 atoms / cm 3 ~2.07×10 14 atoms / cm 3 , the phosphorus concentration is 2.6×10 15 atoms / cm 3 ~6.92×10 13 atoms / cm 3 ; At this time, the resistivity of the single crystal silicon rod is 0.5Ω.cm~1.7Ω.cm.

[0034] Preferably, the antimony concentration in the single crystal silicon rod is 5.37×10 15 atoms / cm 3 ~2.55×10 15 atoms / cm 3 , the phosphorus concentration is 1.79×10 15atoms / cm 3 ~8.5×10 14 atoms / cm 3 At this time, the resistivity of the single crystal silicon rod is 0.7Ω.cm~1.4Ω.cm.

[0035] The present invention also provides a method for preparing the phosphorus-antimony co-doped single crystal silicon rod according to any one of the above embodiments by a Czochralski method, comprising:

[0036] Silicon, phosphorus and antimony are added to the furnace after the previous single crystal silicon rod is processed.

[0037] Phosphorus addition mass M 1P =M 2p -M 3P , where M 2p M is the mass of phosphorus element required to prepare the single crystal silicon rod, in g; 3P is the mass of the remaining phosphorus in the furnace, in g;

[0038] The added mass of antimony element is M 1Sb =M 2Sb +(t2+3)×b Sb -M 3Sb , where M 2Sb M is the mass of antimony element required to prepare the single crystal silicon rod, in g; 3Sb is the mass of the remaining antimony element in the furnace, in g; b Sb is the volatility coefficient of antimony element, b Sb It is 0.1h / g~15h / g; t2 is the interval time between T3 and T4, in h; T3 is the time when the previous single crystal silicon rod is removed after the wire is broken, and T4 is the time when the barrel is removed after the last barrel of silicon material is added.

[0039] In the embodiment of the present invention, the amount of phosphorus added is obtained by subtracting the mass of phosphorus remaining in the furnace from the mass of phosphorus required for preparing the single crystal silicon rod. However, for the antimony element, since antimony is volatile, antimony will volatilize between the time when the last single crystal silicon rod is broken and the time when the last bucket of silicon material is added, resulting in a low content of antimony in the furnace. Therefore, in this application, when determining the mass of antimony added, the antimony addition volatility coefficient is introduced. The addition volatility coefficient is an empirical coefficient. In some embodiments, the addition volatility coefficient of antimony element b SbIt can be 0.1h / g to 15h / g, specifically 0.1h / g, 0.3h / g, 0.5h / g, 1h / g, 3h / g, 5h / g, 7h / g, 9h / g, 11h / g, 13h / g, 15h / g. Generally, the volatilization coefficient of the feed is closely related to the temperature in the furnace between T3 and T4. The higher the temperature in the furnace during this period, the higher the volatilization coefficient of the feed. Sb The value of will be larger.

[0040] In an optional embodiment, the M 2p and M 2Sb It is calculated based on the resistivity of the single crystal silicon rod to be prepared, 3P and M 3Sb It is calculated based on the doping concentration at the tail of the previous single crystal silicon rod.

[0041] Specifically, M 2p and M 3P The calculation of can refer to GB / T 13389-92; because phosphorus and antimony belong to the same family, the outermost structure of atoms in the same family is the same, and a free electron is formed during the doping process, and the electrical properties are the same. Therefore, the resistivity calculation can be calculated according to the phosphorus alloy concentration, but the atomic mass is different, resulting in different doping concentrations. Specifically, M 2Sb and M 3Sb The calculation of can refer to the resistivity of phosphorus alloys, just replace the atomic mass of phosphorus with the atomic mass of antimony.

[0042] In an optional embodiment, the antimony element is added into the furnace before the seed crystal is fused and after the silicon and phosphorus are added.

[0043] The preparation of single crystal silicon rods by the Czochralski method generally includes temperature-controlled melting, seeding, shouldering and equal diameter steps. Usually, doping elements and silicon elements are added to the furnace before temperature-controlled melting. In the present application, antimony element is easily volatile. Therefore, antimony is not added together with phosphorus and silicon, but is added to the furnace before seed crystal melting to ensure that the added material can be melted while reducing volatilization.

[0044] In an optional embodiment, when the crystal pulling wire breaks, the furnace is temperature-adjusted and released 1 to 3 times to compensate for the doped antimony element. The mass of the compensatory doped antimony element each time is M0 = (t1+3)×a, wherein a is the temperature adjustment volatility coefficient of the antimony element, and a is 0.1h / g to 15h / g; t1 is the interval time between T1 and T2, in units of h; wherein T1 is the start time of welding, and T2 is the time when the crystal pulling wire breaks.

[0045] Due to the influence of inaccurate furnace power, crucible position, pulling speed or impurity factors, crystal pulling wire breakage is inevitable. When the crystal pulling wire breakage occurs, it will affect the preparation process of the single crystal silicon rod, and the volatilization of the antimony element will increase, which may cause the doping concentration of antimony in different furnaces or different single crystal silicon rods in the same furnace to deviate, so it is necessary to compensate for the doped antimony element. In this application, when compensating for the doped antimony element, the temperature adjustment volatility coefficient of the antimony element is introduced. The temperature adjustment volatility coefficient is an empirical coefficient. In some embodiments, the temperature adjustment volatility coefficient a of the antimony element can be 0.1h / g~15h / g, specifically 0.1h / g, 0.3h / g, 0.5h / g, 1h / g, 3h / g, 5h / g, 7h / g, 9h / g, 11h / g, 13h / g, 15h / g. Generally, the temperature adjustment volatility coefficient is closely related to the furnace temperature between T1 and T2. The higher the furnace temperature during this time period, the greater the value of a.

[0046] In an optional embodiment, the compensatory doping of antimony element is performed by using a supplementary doping device, the structure of which is as follows: Figure 1 and Figure 2 As shown, it includes a sleeve 100 and a push rod 200 that can move along the inner cavity of the sleeve 100, and one end of the push rod 200 passes through the sleeve 100 and is provided with a hopper 300;

[0047] The sleeve 100 is provided with a guide groove, which includes a push-pull groove 410 arranged along the axial direction of the push rod 200 and a steering groove 420 arranged along the circumference of the push rod 200. A slider 700 that can slide along the guide groove is fixed to one side of the push rod 200 located in the sleeve 100.

[0048] When the supplementary doping device in the present application is used for supplementary doping, the material to be supplemented is added into the hopper 300, and the slider 700 is pushed to move along the push-pull groove 410 to withdraw the push rod 200 from the sleeve 100, and the hopper 300 then reaches the position above the single crystal furnace; then the slider 700 is pushed to rotate along the turning groove 420, and the push rod 200 rotates along the axis of the push rod 200 driven by the push block, thereby driving the hopper 300 to flip, and the material in the hopper 300 is poured into the single crystal furnace, and then the slider 700 moves along the turning groove 420 and the push-pull groove 410 in turn, returns to the initial position, and completes the compensatory doping of antimony elements.

[0049] The embodiment of the present invention further provides a silicon wafer prepared from the phosphorus-antimony co-doped single crystal silicon rod described in the above embodiment, with a resistivity of 0.2Ω.cm to 28Ω.cm and an antimony element concentration of 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , the phosphorus concentration is 7.66×1015 atoms / cm 3 ~3.9×10 13 atoms / cm 3 .

[0050] An embodiment of the present invention further provides a battery, comprising the silicon wafer described in the above embodiment.

[0051] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0052] Example 1

[0053] A method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method (36-inch thermal field), wherein the resistivity of the phosphorus-antimony co-doped single crystal silicon rods to be prepared is 1.0 Ω.cm, and the phosphorus doping concentration is 1.08*10 15 atoms / cm 3 , the antimony doping concentration is 2.88*10 15 atoms / cm 3 , specifically including the following steps:

[0054] 1. After the production is finished, the material is reported. After the processing of the last single crystal silicon rod is completed, there is 360 kg of melt left in the furnace. Add another 600 kg of silicon material into the furnace. The last single crystal silicon rod is cut off at 12:00;

[0055] 2. Material preparation: After receiving the material report from the site, loading is carried out and calculation is carried out in accordance with the national standard GB / T 13389-92;

[0056] M=(W·CT·A) / (d·K0·N0)

[0057] Where: W—weight of polysilicon, g.

[0058] d—Specific gravity of silicon, 2.33 g / cm 3 .

[0059] CT—impurity concentration corresponding to the target resistivity of the single crystal head, atom / cm 3 .

[0060] M—weight of doping element, g.

[0061] A—Atomic weight of the doping element.

[0062] N0—Avogadro constant, 6.023*10 23 .

[0063] M 2p =130g, M 3P =94g, and the added weight of phosphorus is 36g; the resistivity of the tail of the previous single crystal silicon rod is 1.05Ω·m;

[0064] 3. Add phosphorus and silicon raw materials into the barrel and keep records;

[0065] 4. The production is normal. The furnace is charged with materials. After the last barrel is taken out, the material preparation is notified to calculate the antimony alloy. The time is 16:24.

[0066] 5. Prepare the material and calculate the total weight of antimony alloy M by the national standard formula 2Sb =15g, weight of residual antimony alloy M 3Sb =5g, and the weight of antimony alloy to be added is M2+(T3-T4+3)*b-M3=15+(16:24-12:00+3)*0.5-5=15+(4.4+3)*0.5-5=13.7g;

[0067] 6. Send the calculated antimony alloy to the production, and add the antimony alloy into the supplementary doping device before the seed crystal is melted and the temperature is adjusted, and the supplementary doping device is used to add the antimony alloy to complete the alloy doping;

[0068] 7. After the equal diameter is completed, the phosphorus-antimony co-doped single crystal silicon rod A is obtained and finished, and the above steps 1-6 are repeated to continue to produce the phosphorus-antimony co-doped single crystal silicon rod;

[0069] 8. If equal diameter wire breakage occurs during the preparation of single crystal silicon rods, perform the following operations:

[0070] 9. If the production line is broken, click on the line break to notify the material preparation department to add antimony. The line break time is 13:00;

[0071] 10. After receiving the on-site report for material preparation, check the start time of the last welding, the remaining material is 920kg, the time is 1:00, and the weight of antimony alloy to be added is calculated by the formula M0 = (T1-T2+3)*a = (12+3)*0.5 = 7.5g;

[0072] 11. The calculated antimony alloy is sent to the production, and the production adds the antimony alloy into the supplementary doping device before the seed crystal is melted and the temperature is adjusted, and the supplementary doping device is used to add the antimony alloy to complete the alloy doping;

[0073] 12. After the equal diameter is completed, the phosphorus-antimony co-doped single crystal silicon rod B is obtained for finishing, and steps 1-6 are repeated. If the equal diameter wire breakage occurs, steps 9-11 are repeated.

[0074] Comparative Example 1

[0075] A method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method (36-inch hot field), which is different from Example 1 only in that the volatility coefficient b of the added antimony element in step 5 is 0, and M0=0 in step 10.

[0076] Comparative Example 2

[0077] A method for preparing phosphorus single crystal silicon rods by Czochralski method (36-inch hot field), which differs from Example 1 in that only phosphorus element is added in step 2, and the mass of antimony element in step 5 is 0.

[0078] Example 2

[0079] This embodiment provides a method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method (36-inch thermal field). The difference from the embodiment 1 is that the phosphorus doping concentration in the phosphorus-antimony co-doped single crystal silicon rods to be prepared is 7*10 15 atoms / cm 3 , the antimony doping concentration is 1.5*10 14 atoms / cm 3 .

[0080] Example 3

[0081] This embodiment provides a method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method (36-inch thermal field). The difference from the embodiment 1 is that the phosphorus doping concentration in the phosphorus-antimony co-doped single crystal silicon rods to be prepared is 3*10 13 atoms / cm 3 , the antimony doping concentration is 2.3*10 16 atoms / cm 3 .

[0082] Example 4

[0083] This embodiment provides a method for preparing phosphorus-antimony co-doped single crystal silicon rods by the Czochralski method (36-inch hot field). The only difference from Example 1 is that the volatility coefficient of the added antimony element is 0.1h / g, and the temperature-adjusted volatility coefficient of the antimony element is 15h / g.

[0084] Example 5

[0085] This embodiment provides a method for preparing phosphorus-antimony co-doped single crystal silicon rods by the Czochralski method (36-inch hot field). The only difference from Example 1 is that the volatility coefficient of the added antimony element is 15h / g, and the temperature-adjusted volatility coefficient of the antimony element is 0.1h / g.

[0086] Test Example 1:

[0087] Three single crystal silicon rods from each embodiment and comparative example were randomly collected, and the resistivity of the collected single crystal silicon rods was tested. The results are shown in Table 1.

[0088] Table 1

[0089] Head resistance Ω·m Tail resistance Ω·m Difference Ω·m Example 1 1.02 1.05 0.03 Comparative Example 1 1.2 1.29 0.09 Comparative Example 2 1.0 0.6 0.4 Example 2 1.1 1.15 0.05 Example 3 0.82 0.84 0.02 Example 4 0.98 1.01 0.03 Example 5 0.96 0.95 0.01

[0090] Test Example 2:

[0091] The single crystal silicon rods prepared in the above examples and comparative examples were processed and TOPcon cells were manufactured according to the following steps:

[0092] 1. Texturing: The single crystal silicon rods prepared in the above embodiments and comparative examples are cut into N-type raw silicon wafers of corresponding sizes through a slicing process, and the N-type raw silicon wafers are placed in a texturing tank with a NaOH volume concentration of 10%, a temperature of 60°C, and 10L of additives. Subsequently, the wafers are washed with water, acid washed (HF volume concentration of 15%), washed with water, slowly pulled, and dried at a temperature of 90°C.

[0093] 2. Boron expansion: Place the silicon wafer after texturing in a boron expansion tube, with the source temperature at 800°C for 200s and the junction temperature at 1000°C for 1000s.

[0094] 3. Remove BSG + alkali polishing: Etch the boron-expanded silicon wafer on a chain acid etching machine, and the HF volume concentration in the acid tank is 10%.

[0095] 4. Tunneling layer + making amorphous silicon level doping process:

[0096] E-poly in-situ doped amorphous silicon: using PH3 and SiH4 mixed gas, process temperature 400℃.

[0097] 5. RCA de-winding: Silicon oxide is grown on the back of the silicon wafer, and the silicon oxide is washed off the front winding area with HF (volume concentration 20%), and then placed in an alkaline polishing tank (NaOH volume concentration 10%, temperature 70°C, alkaline polishing additive 150L) for alkaline polishing to remove the front polysilicon winding, and obtain a doped polysilicon layer on the tunneling oxide layer on the back;

[0098] 6. The ALO deposition method uses single atomic layer deposition (ALD). The process conditions of the single atomic layer deposition method are: temperature of 230°C, process of TMA, 4 8s purge 7 10s H2O, 4 8s purge 710s, each cycle is to first introduce TMA for 4 8s, purge 7 10s, then introduce water vapor for 4 8s, purge 710s, the number of cycles is 22 51 times. Among them, TMA is Al(CH3)3, TMA and water together form aluminum oxide film. A front silicon nitride layer is formed on the front aluminum oxide layer;

[0099] The front and back SiN layers are deposited by plasma chemical vapor deposition, and the process conditions are: temperature 470°C and pressure 250Pa.

[0100] 7. Carry out printing, sintering, metallization and testing in sequence.

[0101] The efficiency and qualified rate of the TOPCon cells prepared in the above manner were tested, and the results are shown in Table 2.

[0102] Table 2

[0103] Battery efficiency Pass rate Example 1 26.13％ 95.14％ Comparative Example 1 26.07％ 95.11％ Comparative Example 2 26.06％ 95.10％ Example 2 26.11％ 95.12％ Example 3 26.09％ 95.08％ Example 4 26.12％ 95.13％ Example 5 26.10％ 95.10％

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A phosphorus-antimony co-doped single crystal silicon rod, characterized in that: The antimony concentration in the single crystal silicon rod is 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , the phosphorus concentration is 7.66×10 15 atoms / cm 3 ~3.9×10 13 atoms / cm 3 The resistivity difference between the head and tail of a single single crystal silicon rod is less than 0.08Ω.cm.

2. The phosphorus-antimony co-doped single crystal silicon rod according to claim 1, characterized in that: The antimony concentration in the single crystal silicon rod is 2.3×10 16 atoms / cm 3 ~2.07×10 14 atoms / cm 3 , the phosphorus concentration is 2.6×10 15 atoms / cm 3 ~6.92×10 13 atoms / cm 3 ; Preferably, the antimony concentration in the single crystal silicon rod is 5.37×10 15 atoms / cm 3 ~2.55×10 15 atoms / cm 3 , the phosphorus concentration is 1.79×10 15 atoms / cm 3 ~8.5×10 14 atoms / cm 3 .

3. The phosphorus-antimony co-doped single crystal silicon rod according to claim 1, characterized in that: The resistivity of the single crystal silicon rod is 0.2 Ω.cm to 28 Ω.cm, preferably 0.5 Ω.cm to 1.7 Ω.cm, and more preferably 0.7 Ω.cm to 1.4 Ω.cm.

4. A method for preparing the phosphorus-antimony co-doped single crystal silicon rod according to any one of claims 1 to 3 by a Czochralski method, characterized in that: include: Silicon, phosphorus and antimony are added to the furnace after the previous single crystal silicon rod is processed. Phosphorus addition mass M 1P =M 2p -M 3P , where M 2p M is the mass of phosphorus element required to prepare the single crystal silicon rod, in g; 3P is the mass of the remaining phosphorus in the furnace, in g; The added mass of antimony element is M 1Sb =M 2Sb +(t2+3)×b Sb -M 3Sb , where M 2Sb M is the mass of antimony element required to prepare the single crystal silicon rod, in g; 3Sb is the mass of the remaining antimony element in the furnace, in g; b Sb is the volatility coefficient of antimony element, b Sb It is 0.1h / g~15h / g; t2 is the interval time between T3 and T4, in h; T3 is the time when the previous single crystal silicon rod is removed after the wire is broken, and T4 is the time when the barrel is removed after the last barrel of silicon material is added.

5. The method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method according to claim 4, characterized in that: The M 2p and M 2Sb It is calculated based on the resistivity of the single crystal silicon rod to be prepared, 3P and M 3Sb It is calculated based on the doping concentration at the tail of the previous single crystal silicon rod.

6. The method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method according to claim 4, characterized in that: The antimony element is added into the furnace before the seed crystal is melted and after the silicon and phosphorus are added.

7. The method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method according to claim 4, characterized in that: When the crystal pulling wire breaks, the furnace is temperature-adjusted and released 1 to 3 times to compensate for the doped antimony element once. The mass of the doped antimony element M0 each time is compensated = (t1+3)×a, where a is the temperature adjustment volatility coefficient of the antimony element, and a is 0.1h / g~15h / g; t1 is the interval time between T1 and T2, in h; T1 is the start time of welding, and T2 is the time when the crystal pulling wire breaks.

8. The method for preparing phosphorus-antimony co-doped single crystal silicon rods by Czochralski method according to claim 7, characterized in that: The compensatory doping of antimony element is performed by using a supplementary doping device, which comprises a sleeve and a push rod capable of moving along the inner cavity of the sleeve, one end of the push rod passes through the sleeve and is provided with a hopper; The sleeve is provided with a guide groove, which includes a push-pull groove arranged along the axial direction of the push rod and a steering groove arranged along the circumference of the push rod. A sliding block capable of sliding along the guide groove is fixed to one side of the push rod located in the sleeve.

9. A silicon wafer prepared from the phosphorus-antimony co-doped single crystal silicon rod according to claim 1, characterized in that: The resistivity is 0.2Ω.cm~28Ω.cm, and the antimony concentration is 2.3×10 16 atoms / cm 3 ~1.17×10 14 atoms / cm 3 , the phosphorus concentration is 7.66×10 15 atoms / cm 3 ~3.9×10 13 atoms / cm 3 .

10. A battery, characterized in that: Including the silicon wafer as claimed in claim 9.

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