Title：Ion implantation + sub-second annealing: a route towards hyperdoped semiconductors
Speaker： Dr. Shengqiang Zhou
Host： Prof . Xiangyang Ma
Time： July 5, 2018（Thursday） ，10：00 a.m
Place： Conference Room104，Building 1，State Key Laboratory for silicon materials
Abstract：
Doping allows us to modify semiconductor materials for desired electrical, optical and magnetic properties. The solubility limit is a fundamental barrier for dopants incorporated into a specific semiconductor.Hyperdoping refers to doping a semiconductor much beyond the corresponding solid solubility limit and often results in exotic properties. For example, Ga hyperdoped Ge reveals superconductivity and Mn hyperdoped GaAs represents a typical ferromagnetic semiconductor. Ion implantation followed by annealing is a well-established method to dope Si and Ge. This approach has been maturely integrated with the IC industry production line. However, being applied to hyperdoping, the annealing duration has to be shortenedto millisecond or even nanosecond. The intrinsic physical parameters related to dopants and semiconductors (e.g. Solubility, diffusivity, melting point and thermal conductivity) have to be considered to choose the right annealing time regime. In this talk, we propose that ion implantation combined with flash lamp annealing in millisecond and pulsed laser melting in nanosecond can be a versatile approach to fabricate hyperdoped semiconductors. The examples include magnetic semiconductors, highly mismatched semiconductor alloys (Ge1-xSnx and GaAs1-xNx), n++ Ge and chalcogen doped Si.
Bio：
Dr. Zhou Shengqiang received his bachelor's degree in 1996 in the Department of Technical Physics, Peking University, and his doctor's degree in 2007 in the Department of Physics, Dresden University of Technology, Germany. Helmholtz Young Investigator Group Leader, head of the Helmholtz Association of Germany in 2011. He was appointed director of the Institute of semiconductors in the Institute in January 2018, focusing on semiconductor materials, ion irradiated material modification, ion beam analysis, and the application of ion beamsm in magnetic functions of materials. He got the 17 international ion beam material award for young scientists. His doctoral students won the Young Scientist Award and the best Poster award at the international semiconductor Conference (ICPS), the magnetic Conference (ICM) and the European materials (EMRS) conference. He was in charge of the application to the third party funds about 2 million euros as the first person and has published more than 200 papers, which has been cited more than 3500 times. H index is 28.
