Scanning tunneling microscopy and spectroscopy of <i>p</i> <i>n</i> junctions formed by ion implantation

Abstract

Results of scanning tunneling spectroscopy measurements of 〈100〉 n- and p-type silicon are reported. Measurements were made in air on surfaces with a native oxide. Different I/V characteristics were observed for differently doped samples, indicating that the surfaces were unpinned. Images are presented of pn junctions formed by the implantation of phosphorus into boron doped Si wafers. The pn junction, or the boundary between implant and substrate regions, was observed in both constant current and constant height scans. The junction was imaged with 125 Å point-to-point resolution.