Product Code: ICAL09_M904

Direct Laser Doping for High-Efficiency Solar Cells
Authors:
Malte Schulz-Ruhtenberg, Fraunhofer Institute for Laser Technology; Aachen Germany
Jose Luis Hernandez, Imec; Leuven Belgium
Victor Parajapati, Imec; Leuven Belgium
Robert Bleidiessel, Solland Solar Cells Bv; Heerlen Netherlands
Carmen Morilla, Bp Solar; Tres Cantos Spain
Yannick Larmande, Cnrs-Lp3; Marseille France
Vanessa Vervisch, Cnrs-Lp3; Marseille France
Thierry Sarnet, Cnrs-Lp3; Marseille France
Alexander Olowinsky, Fraunhofer Institute for Laser Technology; Aachen Germany
Presented at ICALEO 2009

Renewable energies is a prominent, emerging industry whose momentum suggests surging growth. The promise of a contact-less, precise, high throughput laser tool that enhances solar cell production will be vital in current and future photovoltaic manufacturing. Establishing lasers as an essential part of the manufacturing chain is the major goal of the European funded SOLASYS project ("Next Generation Solar Cell and Modular Laser Processing Systems"). The selective emitter concept is one of the key subjects in the race to grid parity solar cell production. Instead of using an intermediate doping concentration to meet both the demand for high carrier lifetimes and for low contact resistance the doping concentration is increased locally at the positions of the front contacts. This can be achieved by laser doping the contact region before metal deposition. The selection of the proper laser parameters, such as wavelength, pulse length and laser power, allows control of the depth of the doping profile and the dopant concentration.