Arco Solar Inc. formed a venture with Siemens.

Arco Solar, the leading manufacturer of solar cells, said the joint venture with the West German firm will license Siemens Solar GmbH, a member of the Siemens Group of West Germany, to do research based on Arco’s thin-film silicon solar technology. It will also give Arco access to Siemens Solar’s marketing outlets in Europe and might eventually lead to a joint manufacturing plant. Arco wouldn’t put a dollar figure on the venture. It is similar to a venture begun last year between Arco Solar, a unit of Los Angeles-based Atlantic Richfield, and Japan’s Showa Shell Sekiyu.