Tunneling barrier height imaging and polycrystalline Si surface observations

An influence of the dopant concentration on polycrystalline Si grain structure, electronic structure and dopant segregation in 800 °C and 30 min annealing is investigated. Barrier height images and topographies of arsenic implanted polycrystalline silicon surface are obtained using tunneling barrier height imaging (TBI) and scanning tunneling microscopy (STM) with the vacuum pressure less than 5X 10^-7Torr. As results, a conduction band bending caused by the arsenic ion implantation can be observed by the TBI. A comparison of the TBI image with the STM image can identify whether region is implanted or nonimplanted. In addition, dopant segregation structures at the grain boundary can be found out. With dopant concentration, 10¹⁴ cm ^-2As ⁺ implanted polycrystalline silicon grain structures of 4—80 nm size grow large.