A California man was charged today with stealing trade secrets from a Philadelphia-area company that developed pastes used in the manufacture of solar cells.

Authorities said Tung Pham, 46, formerly of Conshohocken and now living near Santa Barbara, worked as a scientist for the company - identified only as Company A in the indictment - from September 2008 until May 3 of this year.

The company had affiliates in Europe, China and Japan.

Pham's work included research and development of silver pastes and lead-free glass for use in silver paste, which is used on the front side of a solar cell.

Prosecutors said Pham had an employment agreement with the company that any projects he worked on while with the company were the property of Company A and that he would take "all reasonable steps necessary to protect any information" regarded by the company as a trade secret from theft.

Instead, Pham allegedly told his supervisor in September 2010 he needed time off for personal reasons.

Prosecutors said that between Sept. 29, 2010 and Oct. 4, 2010, Pham traveled to China where he met with another Company A employee, identified only as "WL."

The indictment said the two subsequently met with investors to plan the creation of a Chinese company that would compete with Company A.

On Oct. 30, 2010, prosecutors charged that Pham signed an employment agreement with a person in China identified as WHZ.

A few weeks later authorities said Pham copied more than 1,000 documents to his home computer that contained the formulations of products Company A was selling.

By Feb. 27, Pham allegedly sent an email to WL in China telling him he would send a revised contract because he was concerned Company A could prevent him from working for the new company under terms of his employment contract with Company A.

After working out details in March to shield the exact nature of his work with the prospective employer and the identity of WHZ, prosecutors said Pham emailed his supervisor on April 11 and resigned from Company A.

Pham is also charged with wire fraud.