Guanghua Song

US Patent:

20100065111, Mar 18, 2010

Filed:

Dec 23, 2008

Appl. No.:

12/343116

Inventors:

Jianming Fu - Palo Alto CA, US
Zheng Xu - Pleasanton CA, US
Peijun Ding - Saratoga CA, US
Chentao Yu - Sunnyvale CA, US
Guanghua Song - Fremont CA, US
Jianjun Liang - Fremont CA, US

Assignee:

SIERRA SOLAR POWER, INC. - Sunnyvale CA

International Classification:

H01L 31/0288

US Classification:

136255, 117 78

Abstract:

One embodiment of the present invention provides a method for fabricating a solar cell. The method includes: melting a metallurgical-grade (MG) Si feedstock, lowering a single-crystalline Si seed to touch the surface of the molten MG-Si, slowly pulling out a single-crystal Si ingot of the molten MG-Si, processing the Si ingot into single crystal Si wafers to form MG-Si substrates for subsequent epitaxial growth, leaching out residual metal impurities in the MG-Si substrate, epitaxially growing a layer of single-crystal Si thin film doped with boron on the MG-Si substrate, doping phosphor to the single-crystal Si thin film to form an emitter layer, depositing an anti-reflection layer on top of the single-crystal Si thin film, and forming the front and the back electrical contacts.

US Patent:

20130252427, Sep 26, 2013

Filed:

Mar 26, 2012

Appl. No.:

13/430587

Inventors:

Guanghua Song - Fremont CA, US

Assignee:

SUNPREME, LTD. - Sunnyvale CA

International Classification:

H01L 21/311
B44C 1/22
C23G 1/02
B08B 3/08
C23G 1/14

US Classification:

438694, 134 254, 134 2, 134 3, 216 83, 257E21249

Abstract:

Substrates for solar cells are prepared by the reverse of the standard RCA clean. The substrates are first cleaned in RCA-2 solution and then in RCA-1 solution. A pyramids rounding step using HF/HNOsolution is inserted between the two RCA clean procedures. This solves all the issues relating to surface contaminations and sharp areas. It also avoids the stain layer on the surface to some extent by RCA-1 treatment. A thin layer of amorphous or micro-crystalline intrinsic silicon may be deposited to passivate the surface.