Trench process and structure for backside contact solar cells with polysilicon doped regions

US7812250B2 · kind B2 · utility

Assignee

• SUNPOWER CORPORATION · US

Inventor

• David D. Smith · Dublin, US

Key dates

• Filing date: Apr 28, 2009
• Grant date: Oct 12, 2010
• Expiry date: Apr 28, 2029

Classification

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

Abstract

A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. A trench structure separates the P-type doped region from the N-type doped region. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. The trench structure may include a textured surface for increased solar radiation collection. Among other advantages, the resulting structure increases efficiency by providing isolation between adjacent P-type and N-type doped regions, thereby preventing recombination in a space charge region where the doped regions would have touched.