In Memoriam: Jochen Biersack, Nathan Cheung and Russell Gwilliam

Summary form only given, as follows. The Ion Implantation Technology community lost three longtime leaders of ion implantation and related technologies. They are missed by many of the IIT community. Jochen Biersack, an expert in particle-solid interactions, worked closely with Jim Ziegler to develop the Transport of Ions in Matter (TRIM) simulation program and worked continually to encourage global use of this program by particle beam scientists and engineers. TRIM found uses ranging from ion implantation to space physics to nuclear fusion. Jochen was an eager supporter of the IIT conference series in its early years. Nathan Cheung joined the Electrical Engineering and Computer Science faculty at UC Berkeley, after his PhD with Jim Mayer at Cal Tech in 1980 and retired in 2014. Nathan was an enthusiastic explorer of many innovations in semiconductor processing including the early development of Plasma Immersion Ion Implantation (PIII) starting from 1988. Nathan was the co-chair of IIT-86 in Berkeley and served as a member of the IIT International Committee for many years. Russell Gwilliam joined the ion beam research group at the U. of Surrey after his PhD. with Brian Sealy and later became a Professor of Semiconductor Process and Director of Technology at the Surrey Ion Beam Centre. Russ had a broad appreciation of the use of ion beams for modification and analysis of materials and collaborated with an astounding range of people across the world while coaching a long stream of students in the arts of ion accelerators while publishing over 350 papers. Russ was the co-chair of IIT-06 in Marseilles and was a lively and generous contributor on the IIT International Committee.