Purpose: Remove surface soiling and cut damage layers to form trapping structures;

Method: Form pyramidal structures by anisotropic etching in hot alkaline solution.

Purpose: Form PN junctions by doping to create a built-in electric field and separate carriers;

Method: Form P+ layer by diffusion of BCl3 at high temperature to create a built-in electric field.

Purpose: Form a heavy doping region in the metal electrode region and keep the light doping in the rest of the region;

Method: Form selective doping by SE laser in the metal electrode region.

Purpose: Repair the laser-damaged BSG in the SE heavy doping region to act as a protection;

Method: Repair by thermal oxidation at high temperature to form intact BSG.

Purpose: Remove the BSG on the back and sides;

Method: Etch the BSG at the back and sides in the chain structure by utilizing HF.

Purpose: The backside polishing smoothens the silicon wafer surface, improving the uniformity of the oxidation tunneling layer and the passivation effect, thereby enhancing the photovoltaic conversion efficiency of solar cells.

Method: Using a trench-style alkaline solution to remove the pyramid velvet surface on the backside, forming a smooth base structure.

Purpose: Form tunnel oxide and selective passivation structure of amorphous silicon layers on the backside.

Method: PECVD in-situ doping to form backside ultra-thin SiOx and n+ amorphous silicon layers.

Purpose: Convert amorphous silicon surfaces to polycrystalline silicon and activate P to form doped n+ structures.

Method: Crystallize amorphous silicon by high temperature while activating phosphorus and forming electron tunneling channels.

Purpose: Remove PSG from the plating around the sides and front.

Method: Etch the PSG at the front and sides in the chain structure by utilizing HF.

Purpose: Remove n-poly Si on the side and BSG/PSG on the front and back.

Method: Etch n-poly Si in tank hot alkaline solution, and etch BSG/PSG by HF.

Purpose: Provide surface passivation and field passivation effects on AlOx films to improve open voltage and reduce surface composite in solar cells.

Method: Via TMA utilizing atomic layer deposition to grow double-sided AlOx films.

Purpose: Deposit SiNx antireflection films to reduce light reflection and prevent oxidation.

Method: Grow SiNx antireflection films by ionization decomposition of the fluent SiH4/NH3 using PECVD.

Purpose: Print metal paste on the surface of silicon wafers and form conductive electrodes to draw current after sintering.

Method: Print main and sub grids on the front and back side in steps, and form metal electrodes after sintering.

Purpose: Test and sort the finished products and pack them according to different grades and powers.

Method: Sort and package finished battery products by grade and power through AOI, EL and electrical performance testing.