The correspondence among direct competitors in the memory chip business suggests they traded information to keep prices up, the Journal said on Thursday.
Some of the e-mails also suggestto keep prices low to discourage use of Rambus's double data rate, or DDR, technology, according to the Journal, which was given access to the e-mails by Rambus.
Rambus has filed antitrust claims in San Francisco County Superior Court against companies that have also been implicated in a Justice Department investigation into price fixing. These companies include Micron, Hynix and Samsung Electronics.
The Justice Department's probe, launched in 2002, has resulted in more than $731 million in fines on Samsung, Hynix, Infineon Technologies and Elpida Memory, the Journal reported.
Lawyers for Micron and Hynix told the Journal that they disputed Rambus's assertions.
"Rambus's publication of these documents takes them out of context and ascribes to them Rambus's inaccurate, litigation-driven interpretations," a Hynix spokeswoman said in a statement given to the Journal. "Hynix did not participate in any conspiracy against Rambus and looks forward to proving that fact in the appropriate judicial forum."
Micron and Rambus spokesmen were not immediately reachable.
The e-mails were gathered by the U.S. Justice Department and released to Rambus, the Journal reported.