According to the one-count felony charge filed in U.S. District Court in San Francisco, Heinrich Florian, Gunter Hefner, Peter Schaefer and T. Rudd Corwin were found guilty of conspiring to fix DRAM chip prices between 1999 and 2002. Except for Corwin, a U.S. citizen, the executives are all German citizens.

Each has agreed to pay a $250,000 criminal fine and serve prison terms ranging from four to six months. In addition, the executives agreed to assist an ongoing government probe into possible price fixing in the DRAM industry.

"These four executives are the first to plead guilty to a charge of fixing prices in what is still a very active and far-reaching investigation into antitrust violations in the DRAM industry," said Scott Hammond, the director of criminal enforcement for the Justice Department's antitrust department, in a statement.

The pleas come two months after Munich-based Infineon agreed to plead guilty to price-fixing charges in the DRAM industry and pay a $160 million fine, the third largest in antitrust history.

DRAMs, which account for $5 billion in U.S. sales annually, are the most common semiconductor memory product. The market is dominated by large suppliers such as Infineon, Micron Technology Inc., Samsung Electronics Co. Ltd. and Hynix Semiconductor Inc.

Previously, Micron Technology regional sales manager Alfred Censullo pleaded guilty to obstructing justice in connection with the Dept. of Justice's DRAM price-fixing investigation.