In order to investigate surface chemistry in greater detail an approach has been adopted whereby thin film formation is examined in situ using the powerful techniques of surface science. In this abstract the results of pyrolytic, photolytic and electron beam deposition studies of Fe from Fe(CO)//5 on Si (100) are summarized. All experiments were carried out in a stainless steel ultra-high-vacuum chamber equipped for LEED, AES and thermal desorption experiments. Clean Si surfaces were produced in vacuo and AES showed less than 0. 2% surface contamination
