AVS 49th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP29
Studies of Ballistic Electron Emission Microscopy on p-n Junction Structures

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Surface Science Poster Session
Presenter: E.R. Heller, The Ohio State University
Authors: E.R. Heller, The Ohio State University
J.P. Pelz, The Ohio State University
C. Tivarus, The Ohio State University
Correspondent: Click to Email
One class of experiments using Ballistic Electron Emission Microscopy (BEEM) makes nm-scale studies of hot-electron transport through a deposited film@footnote 1@ or 'stack' of metal films (e. g. magnetic multilayers)@footnote 2@ and/or insulating layers (e. g. magnetic tunnel junctions).@footnote 3@ For this class of experiments, a high quality (non-leaky) metal/semiconductor Schottky has been required to block thermal electrons. However, desired film deposition techniques (e.g. sputtering) and non-ideal surface preparation often produce very leaky and non-uniform Schottky barriers, making BEEM studies complicated or impossible. We will discuss an alternate approach for such studies which uses a buried pn junction in the semiconductor as the thermal electron blocking layer. We find this permits much higher signal-to-noise for sample structures which are incompatible with good Schottky barriers. By putting the blocking layer inside the bulk of the semiconductor, a leaky or non-ideal metal/semiconductor interface becomes largely irrelevant. A well-designed pn junction still can have low hot-electron attenuation@footnote 4@ and extremely good rejection of thermal electrons. We will also discuss related on-going approaches which can permit BEEM studies at reduced temperatures with sensitivity down to the aA (10@super -18@ amp) level. This work was supported by NSF Grant No. DMR-0076362. @FootnoteText@ @footnote 1@Lu R. P. et al., J Appl. Phys. 87, 5164 (2000).@footnote 2@W. H. Rippard and R. A. Buhrman, Appl. Phys. Lett. 75, 1001 (1999).@footnote 3@W. H. Rippard, A. C. Pirella, and R. A. Buhrman, Appl. Phys. Lett. 78, 1601 (2001).@footnote 4@L. D. Bell et al., Phys. Rev. B 48, 5712 (1993).