CO2laser‐induced melting of heavily doped silicon (>1018cm−3) was studied using both nanosecond and picosecond laser pulses. Evidence for melting is presented and the duration of the melting was measured at intensities below the damage threshold. Dense plasma formation was observed before melting occurred. The melt durations were considerably longer than reported previously for visible laser pulses of comparable durations, indicating a very deep (≳1 &mgr;m) molten layer had been achieved.