AVS 50th International Symposium
    Electronic Materials and Devices Monday Sessions
       Session EM+SC-MoA

Invited Paper EM+SC-MoA5
Nanoscale Electronic Characterization of Semiconductors: from Operating Devices to Atomic Scale Defects

Monday, November 3, 2003, 3:20 pm, Room 321/322

Session: Defects and Interfaces in Electronic Materials and Devices
Presenter: Y. Rosenwaks, Tel-Aviv University, Israel
Authors: Y. Rosenwaks, Tel-Aviv University, Israel
R. Shikler, Tel-Aviv University, Israel
Th. Glatzel, Hahn-Meitner Institut, Germany
S. Sadewasser, Hahn-Meitner Institut, Germany
Correspondent: Click to Email
Scanning probe microscopy has opened new opportunities to image semiconductors electronic properties with unprecedented spatial resolution. The recently developed Kelvin probe force microscopy (KPFM) technique has already been demonstrated as a powerful tool for measuring nanoscale electronic properties and has found many diverse applications in recent years. In this talk several novel applications of the KPFM technique recently developed and demonstrated by our group will be presented. The long-range electrostatic force between the AFM tip and the semiconductor surface deteriorates drastically the KPFM spatial resolution, and poses the problem whether surface atomic scale defects can be quantitatively measured. In addition, the physical understanding of the observed contrast in atomic resolution images is still under discussion. We show that by combining ultrahigh vacuum (UHV) KPFM measurements with rigorous modelling of the tip-semiconductor electrostatic interaction it is possible to extract the surface charge density at the atomic steps of a GaP (110 ) surface. The third part of the talk will be devoted to the use of KPFM for direct measurement of surface states parameters in semiconductors. The method is based on the measurement of very asymmetric cleaved p++n or n++p junctions. The absolute surface band bending, Us, and the surface charge density, Nss, can can be extracted because one side of the junction is degenerate, and all the band bending is taking place in the low doped semiconductor. Methods to obtain the surface states energy distribution are also discussed.