The Justice Department is considering legislation that would give full or partial antitrust immunity to companies that cooperate on research and development efforts.

Assistant Attorney General William F. Baxter said yesterday that several possible approaches are being considered, but the administration has not yet adopted a position. He is scheduled to testify on the issue today before a Senate subcommittee.

Baxter's antitrust division already has proposed that customary antitrust triple-damage penalties should not apply to companies that are found to violate antitrust laws by sharing research and development results. Judgments in such cases--as in other, less-flagrant antitrust violations--should be limited to single rather than triple damages, Baxter has urged.

He said that another approach might be to bar private antitrust suits against joint R&D ventures unless the government first brings a suit, or to raise other, more limited obstacles to such private suits.

A group of computer firms led by Control Data Corp. has formed a highly publicized joint R&D effort to strengthen their competitive position against the Japanese and other foreign competitors.

Baxter told the group, Microelectronics & Computer Technology Corp., that the Justice Department would not object to the venture, but would monitor its specific activities to see if antitrust concerns are raised. "We're not giving them a green light to do anything they wish in the future," a Justice official said.