when at stop light or full stop the engine revs up with brake pedal depressed on 2000 Saturn SL1

the harder i put the brake pedal down the more it revs up; then it will just return to normal --- doesnt happen all the time at periodic times

2 answers
seek diag on this as someone needs to see car to give an opinion
What does it do when in park? normal idle , but then fluctuates when stepping on brake pedal? If so have brake booster checked.