AVS 47th International Symposium
    Thin Films Wednesday Sessions
       Session TF+EL-WeA

Paper TF+EL-WeA3
Near-edge Valence Band Structure of Amorphous Hydrogenated SiC Thin Films by a Combined use of Auger and Photoemission Processes

Wednesday, October 4, 2000, 2:40 pm, Room 203

Session: In-situ Characterization of Thin Film Growth
Presenter: M.-H. Lee, University of Washington
Authors: M.-H. Lee, University of Washington
F.S. Ohuchi, University of Washington
Correspondent: Click to Email
Although x-ray photoelectron spectroscopy (XPS) nominally provides useful information about the valence-band (VB) electron density of state (DOS), the VB leading edges for Si-C alloys are not adequately evaluated due to large difference in the photoionization cross-sections between Si-3p and C-2p. A core-valence-valance (CVV) Auger transition contains information about the local valence electronic structure of the probed atom due to the direct coupling of the core and valence levels in the Auger process. In addition, the Auger matrix elements give clear pictures of top and maximum of p-like local density of states (LDOS) around Si and C in the near-edge VB region. In this talk, a combined use of the Auger and photoemission processes for site-specific information about the local density of states (LDOS) and the leading edge in the VB will be described. Binding energy-corrected Auger line shape for each of Si and C was obtained to identify the valence electronic structure in the particular case of amorphous hydrogenated SiC (a-Si@sub 1-x@C@sub x@:H) thin films fabricated by plasma enhanced chemical vapor deposition. In the C-rich region (x @>=@ 0.6), the leading VB edge was defined by C-2p, while the VB edge was determined by both Si-3p and C-2p in Si-rich region (x < 0.6). The conduction band (CB) edge was assigned by electron energy loss spectroscopy (EELS) with Si-2p electron-associated energy loss. The band gap energies obtained from the VB and CB edges were compared to those from optical absorption measurements.