Application Note for Leica EM RES102 – Previous studies showed that surface accumulation of In occurs when InP was milled in a conventional way with Ar ions. The consequence is In islands on the sample surface. This leads to low quality of TEM samples. To remove these islands, reactive ion milling with iodine ions (RIBE / CAIBE) can be used. This method has the disadvantage of polluting the ion guns and the vacuum system of the ion milling device and leads to chemical reactions with the sample material. To avoid these problems we prepared these samples very gently with low energy Ar ions.