Solar cell and method of manufacture

US7897867B1 · kind B1 · utility

Assignee

• SUNPOWER CORPORATION · US

Inventors

• William P. Mulligan · San Jose, US
• Michael Cudzinovic · Sunnyvale, US
• Thomas Pass · San Jose, US
• David D. Smith · Dublin, US
• Neil Kaminar · Santa Cruz, US
• Keith McIntosh · Mona Vale, AU
• Richard M. Swanson · Los Altos, US

Key dates

• Filing date: Feb 13, 2008
• Grant date: Mar 1, 2011
• Expiry date: Jul 7, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/50

Abstract

A solar cell that is readily manufactured using processing techniques which are less expensive than microelectronic circuit processing. In preferred embodiments, printing techniques are utilized in selectively forming masks for use in etching of silicon oxide and diffusing dopants and in forming metal contacts to diffused regions. In a preferred embodiment, p-doped regions and n-doped regions are alternately formed in a surface of the wafer through use of masking and etching techniques. Metal contacts are made to the p-regions and n-regions by first forming a seed layer stack that comprises a first layer such as aluminum that contacts silicon and functions as an infrared reflector, second layer such titanium tungsten that acts as diffusion barrier, and a third layer functions as a plating base. A thick conductive layer such as copper is then plated over the seed layer, and the seed layer between plated lines is removed. A front surface of the wafer is preferably textured by etching or mechanical abrasion with an IR reflection layer provided over the textured surface. A field layer can be provided in the textured surface with the combined effect being a very low surface recombinatio…