Passivated contact structure and preparation method thereof, and solar cell and preparation method thereof

1 . A preparation method of a passivated contact structure, comprising:

forming a tunneling layer on a semiconductor substrate;

forming an intrinsic semiconductor layer on the tunneling layer;

forming a doped layer containing a dopant on the intrinsic semiconductor layer; and

performing an activation treatment on the doped layer to diffuse the dopant in the doped layer into the intrinsic semiconductor layer to form a doped semiconductor layer;

wherein the tunneling layer and the doped semiconductor layer form the passivated contact structure, and

wherein a first thermal treatment is performed subsequent to forming the intrinsic semiconductor layer and prior to forming the doped layer, thereby reducing the defect state density of the intrinsic semiconductor layer to help achieve effective higher-concentration doping, thereby providing a better field passivation effect.

2 . The preparation method according to claim 1 , wherein the intrinsic semiconductor layer is formed by a plasma enhanced chemical vapor deposition (PECVD) process.

3 . The preparation method according to claim 2 , wherein a process gas of the PECVD process comprises a silicon source gas and a diluent gas.

4 . The preparation method according to claim 3 , wherein a ratio of a flow rate of the diluent gas to a flow rate of the silicon source gas is greater than or equal to 1.5;

and/or, the silicon source gas comprises at least one of SiH 4 , Si 2 H 6 , SiCl 3 H, and SiH 2 Cl 2 ;

and/or, the diluent gas comprises at least one of H 2 , Ar, N 2 , He, and Xe.

5 . The preparation method according to claim 2 , wherein, in the PECVD process, the process gas is excited using a microwave power supply or a radio frequency power supply; and

power of the power supply ranges from 6000 W to 15000 W, and/or, a frequency of the power supply ranges from 30 KHz to 250 KHz.

6 . The preparation method according to claim 2 , wherein a deposition rate of the intrinsic semiconductor layer ranges from 2 nm/min to 20 nm/min;

and/or, a chamber pressure during the PECVD process ranges from 500 mTorr to 5000 mTorr;

and/or, a chamber temperature during the PECVD process ranges from 350° C. to 480° C.

7 . The preparation method according to claim 1 , wherein the first thermal treatment is performed on the intrinsic semiconductor layer to control a crystalline fraction of the intrinsic semiconductor layer to be a first preset value.

8 . The preparation method according to claim 7 , wherein a treatment temperature of the first thermal treatment ranges from 600° C. to 850° C., and a treatment time of the first thermal treatment is greater than or equal to 5 min;

and/or, the first preset value is greater than or equal to 10%.

9 . The preparation method according to claim 1 , wherein a reaction gas is supplied into a reaction chamber, and the doped layer is formed at a first preset temperature.

10 . The preparation method according to claim 9 , wherein the reaction gas comprises a doping source gas and oxygen;

and/or, the first preset temperature ranges from 700° C. to 850° C.

11 . The preparation method according to claim 1 , wherein, in the performing the activation treatment on the doped layer to diffuse the dopant in the doped layer into the intrinsic semiconductor layer to form the doped semiconductor layer, a second thermal treatment is performed on the doped layer and the intrinsic semiconductor layer to activate the doped layer and control a crystalline fraction of the intrinsic semiconductor layer to be a second preset value.

12 . The preparation method according to claim 11 , wherein a treatment temperature of the second thermal treatment ranges from 850° C. to 1000° C., and a treatment time of the second thermal treatment ranges from 3 min to 90 min;

and/or, the second preset value is greater than or equal to 60%.

13 . The preparation method according to claim 1 , further comprising:

removing the doped layer.

14 . A preparation method of a solar cell, comprising the preparation method of the passivated contact structure according to claim 1 .

15 . The preparation method according to claim 14 , further comprising:

forming a dielectric layer on a side of the doped semiconductor layer away from the semiconductor substrate; and

forming a first electrode on the side of the doped semiconductor layer away from the semiconductor substrate, a first end of the first electrode extending through the dielectric layer and part of the doped semiconductor layer and being electrically connected to the doped semiconductor layer, and a second end of the first electrode extending in a direction away from the semiconductor substrate.