You can use "fix deposit" command for sputtering process. Read about this command on https://lammps.sandia.gov/doc/fix_deposit.html. There is one example file called "deposit" in the Lammps>Examples derectory which will make you familier with the use of "fix deposit". You can asign specific sputtering energy to the addatoms by using Kignetic Energy relation with atomic mass and velocity of sputtering ions.

As stated by Bhaveshkumar, there is an example within the LAMMPS example directory. I also put together a sputtering example for a workshop I gave during my time at UofA, you can find it here:

http://u.arizona.edu/~stefanb/Codes/LAMMPS_Files/lammps_ex3.tar.gz

Thank you very much i will try this