AVS 47th International Symposium
    Semiconductors Friday Sessions
       Session SC+EL-FrM

Paper SC+EL-FrM6
Field Electron Emission and Surface Properties of as-grown and Modified AlGaN Films

Friday, October 6, 2000, 10:00 am, Room 306

Session: III-Nitride Processing and Devices
Presenter: A. Tempez, University of Houston
Authors: A. Bensaoula, University of Houston
I. Berishev, University of Houston
E. Kim, University of Houston
M. Ugarov, General Physics Institute, Russia
V. Ageev, General Physics Institute, Russia
E. Loubnin, General Physics Institute, Russia
A. Karabutov, General Physics Institute, Russia
A. Tempez, University of Houston
Correspondent: Click to Email
The correlation between surface morphology and composition, Si substrate orientation and field emission properties of Al@sub x@Ga@sub1-x@N and GaN/AlN films was investigated. It was demonstrated that a high Ga surface density provides thin films with better field electron emission characteristics such as a higher emission current and lower voltage threshold. It was found that a proper choice of the substrate orientation is crucial to obtaining the desired electronic properties since it plays a major role in the resulting thin film surface microstructure. A post-growth modification by X-ray irradiation was also performed on these films. Our results show a significant improvement in the field emission characteristics of the Al@sub x@Ga@sub1-x@N surfaces. The threshold field was reduced by up to three times and current density increased up to 10 A/cm@super2@. These results are consistent with data previously obtained for field emission and laser photoconductivity enhancement by X-ray irradiation of BN thin films. The effect of the X-ray induced generation of additional density of states in the nitride material band gap, on the changes in film conductivity and surface potential barrier height will be discussed. The project was funded in part by a CRDF Grant assistance program (Project # RP0-698), a Russian Federation for Basic Research grant (# 99-02-16653) and a NASA Cooperative agreement #NCC8-127 to the Space Vacuum Epitaxy Center.